• C# 通过子窗体刷新父窗体：窗体控制

    目录

    1、实现方法 

    2.SqlCommand类

    3.实例的主窗体Frm_Main： 

    （1）Frm_Main.Designer.cs

    （2）Frm_Main.cs

    4.实例的子窗体Frm_Child： 

    （1） Frm_Child.Designer.cs

    （2）Frm_Child.cs

    5.生成效果

    （1）生成

    （2）添加

    （3）添加后

    （4）清空

            在一些软件，比如，进销存管理系统中添加销售单信息时，每个销售单都可能对应多种商品，而且在向销售单中添加商品时，一般都是在新弹出的窗体中选择商品，这时就涉及通过子窗体刷新父窗体的问题。

    1、实现方法 

            实现通过子窗体刷新父窗体时，主要通过在自定义事件中执行数据绑定来对主窗体进行刷新，即当子窗体产生更新操作时，通过子窗体的一个方法触发主窗体中对应的事件，这个过程主要用到了EventHandler事件。

            EventHandler事件主要是通过EventHandler委托来实现的，该委托表示处理不包含事件数据的事件的方法。语法格式如下：

    1. public delegate void EventHandler(Object sender,EventArgs e)
    3. 参数说明
    4. Sender：事件源。
    5. e：不包含任何事件数据的EventArgs事件数据。

            例如，通过使用EventHandler事件为子窗体添加一个事件处理程序，以便能够刷新父窗体中的数据。

            在子窗体里：

    1. /// 
    2. /// 某一个事件，比如，添加
    3. /// 
    4. private void Button1_Click(object? sender, EventArgs e)
    5. {
    6.     GlobalFlag = true;                          //设定标识的值为true
    7.     if (!(comboBox1.Items.Equals(idContent)))   //当Combobox控件中不存在将添加的信息时
    8.     {
    9.         comboBox1.Items.Add(idContent!);        //在Combobox控件中添加一条记录
    10.     }
    11.     UpdateData();
    12. }
    13.  
    14. // 其它
    15.  
    16. /// 
    17. /// 更新DataGridView控件中的内容
    18. /// 
    19. protected void UpdateData()
    20. {
    21.     UpdateDataGridView?.Invoke(this, EventArgs.Empty);
    22. }

             在主窗体里：

    1. // 添加子窗体的事件
    2. public void CreateFrmChild()
    3. {
    4.     Frm_Child BabyWindow = new()
    5.     {
    6.         MdiParent = this,
    7.     };
    8.     dataGridView1.Controls.Add(BabyWindow);
    9.     BabyWindow.UpdateDataGridView += new EventHandler(BabyWindow_UpdateDataGridView!);
    10.     BabyWindow.Show();
    11. }
    12.  
    13. // 其它
    14.  
    15. /// 
    16. /// 实现事件委托
    17. /// 
    18. void BabyWindow_UpdateDataGridView(object sender, EventArgs e)
    19. {
    20.     // 其它
    21. }

    2.SqlCommand类

            本实例中使用了SQL，主窗体的数据读取自SQL，在子窗体里更新，然后回写SQL，其结果再次更新到主窗体。

            在C#中执行SQL语句时，可以使用SqlCommand类，该类主要用于向SQL Server数据库发送SQL语句。

            本实例的数据库连接字符串：

    1. //数据库连接字符串
    2. readonly string? ConnString = "Data Source=DESKTOP-3LV13FS;DataBase=db_TomeOne;integrated security=SSPI;TrustServerCertificate=true;";

            还有，在.NET 8.0中，要使用命名空间：using Microsoft.Data.SqlClient;因为 using System.Data.SqlClient; 已经废弃。

    3.实例的主窗体Frm_Main： 

    （1）Frm_Main.Designer.cs

    1. namespace _197
    2. {
    3.     partial class Frm_Main
    4.     {
    5.         /// 
    6.         ///  Required designer variable.
    7.         /// 
    8.         private System.ComponentModel.IContainer components = null;
    9.  
    10.         /// 
    11.         ///  Clean up any resources being used.
    12.         /// 
    13.         /// true if managed resources should be disposed; otherwise, false.
    14.         protected override void Dispose(bool disposing)
    15.         {
    16.             if (disposing && (components != null))
    17.             {
    18.                 components.Dispose();
    19.             }
    20.             base.Dispose(disposing);
    21.         }
    22.  
    23.         #region Windows Form Designer generated code
    24.  
    25.         /// 
    26.         ///  Required method for Designer support - do not modify
    27.         ///  the contents of this method with the code editor.
    28.         /// 
    29.         private void InitializeComponent()
    30.         {
    31.             menuStrip1 = new MenuStrip();
    32.             toolStripMenuItem1 = new ToolStripMenuItem();
    33.             toolStripMenuItem2 = new ToolStripMenuItem();
    34.             toolStripMenuItem3 = new ToolStripMenuItem();
    35.             dataGridView1 = new DataGridView();
    36.             menuStrip1.SuspendLayout();
    37.             ((System.ComponentModel.ISupportInitialize)dataGridView1).BeginInit();
    38.             SuspendLayout();
    39.             // 
    40.             // menuStrip1
    41.             // 
    42.             menuStrip1.BackColor = SystemColors.ControlDark;
    43.             menuStrip1.Items.AddRange(new ToolStripItem[] { toolStripMenuItem1 });
    44.             menuStrip1.Location = new Point(0, 0);
    45.             menuStrip1.Name = "menuStrip1";
    46.             menuStrip1.Size = new Size(335, 25);
    47.             menuStrip1.TabIndex = 0;
    48.             menuStrip1.Text = "menuStrip1";
    49.             // 
    50.             // toolStripMenuItem1
    51.             // 
    52.             toolStripMenuItem1.DropDownItems.AddRange(new ToolStripItem[] { toolStripMenuItem2, toolStripMenuItem3 });
    53.             toolStripMenuItem1.Name = "toolStripMenuItem1";
    54.             toolStripMenuItem1.Size = new Size(44, 21);
    55.             toolStripMenuItem1.Text = "操作";
    56.             // 
    57.             // toolStripMenuItem2
    58.             // 
    59.             toolStripMenuItem2.Name = "toolStripMenuItem2";
    60.             toolStripMenuItem2.Size = new Size(136, 22);
    61.             toolStripMenuItem2.Text = "添加或删除";
    62.             toolStripMenuItem2.Click += ToolStripMenuItem2_Click;
    63.             // 
    64.             // toolStripMenuItem3
    65.             // 
    66.             toolStripMenuItem3.Name = "toolStripMenuItem3";
    67.             toolStripMenuItem3.Size = new Size(136, 22);
    68.             toolStripMenuItem3.Text = "退出";
    69.             toolStripMenuItem3.Click += ToolStripMenuItem3_Click;
    70.             // 
    71.             // dataGridView1
    72.             // 
    73.             dataGridView1.AllowUserToAddRows = false;
    74.             dataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
    75.             dataGridView1.Dock = DockStyle.Fill;
    76.             dataGridView1.Location = new Point(0, 25);
    77.             dataGridView1.Name = "dataGridView1";
    78.             dataGridView1.Size = new Size(335, 178);
    79.             dataGridView1.TabIndex = 1;
    80.             // 
    81.             // Frm_Main
    82.             // 
    83.             AutoScaleDimensions = new SizeF(7F, 17F);
    84.             AutoScaleMode = AutoScaleMode.Font;
    85.             ClientSize = new Size(335, 203);
    86.             Controls.Add(dataGridView1);
    87.             Controls.Add(menuStrip1);
    88.             IsMdiContainer = true;
    89.             MainMenuStrip = menuStrip1;
    90.             Name = "Frm_Main";
    91.             Text = "主窗体";
    92.             Load += Frm_Main_Load;
    93.             menuStrip1.ResumeLayout(false);
    94.             menuStrip1.PerformLayout();
    95.             ((System.ComponentModel.ISupportInitialize)dataGridView1).EndInit();
    96.             ResumeLayout(false);
    97.             PerformLayout();
    98.         }
    99.  
    100.         #endregion
    101.  
    102.         private MenuStrip menuStrip1;
    103.         private ToolStripMenuItem toolStripMenuItem1;
    104.         private ToolStripMenuItem toolStripMenuItem2;
    105.         private ToolStripMenuItem toolStripMenuItem3;
    106.         private DataGridView dataGridView1;
    107.     }
    108. }

    （2）Frm_Main.cs

    1. // 通过子窗体刷新父窗体
    2. // 设置主窗体的IsMdiContainer=true;
    3. using System.Data;
    4. using Microsoft.Data.SqlClient;
    5.  
    6. namespace _197
    7. {
    8.     public partial class Frm_Main : Form
    9.     {   
    10.         public Frm_Main()
    11.         {
    12.             InitializeComponent();
    13.         }
    14.  
    15.         #region 声明的变量
    16.         private static bool flag = false;   //标识是否创建新的子窗体
    17.         readonly Frm_Child BabyWindow = new();//实例化一个子窗体
    18.         readonly DataSet PubsSet = new();   //定义一个数据集对象
    19.         private static string[]? iDArray;   //声明一个一维字符串数组
    20.         public DataTable? IDTable;          //声明一个数据表对象
    21.         SqlDataAdapter? IDAdapter;          //声明一个数据读取器对象
    22.         SqlDataAdapter? PubsAdapter;        //声明一个数据读取器对象
    23.         SqlConnection? ConnPubs;            //声明一个数据库连接对象
    24.         SqlCommand? PersonalInformation;    //声明一个执行SQL语句的对象
    25.  
    26.         public static string[]? IDArray { get => iDArray; set => iDArray = value; }
    27.         public static bool Flag { get => flag; set => flag = value; }
    28.         
    29.         readonly string? ConnString         //数据库连接字符串
    30.             = "Data Source=DESKTOP-3LV13FS;DataBase=db_TomeOne;integrated security=SSPI;TrustServerCertificate=true;";
    31.         #endregion
    32.  
    33.         private void Frm_Main_Load(object? sender, EventArgs e)
    34.         {
    35.             string AdapterString = "select userID as 编号,userName as 姓名 ,phone as 电话,address as 住址 from tb_User";//用于查询的字符串
    36.             string IDString = "select userID from tb_User";//读取数据库中用户的ID编号字符串
    37.             ConnPubs = new SqlConnection(ConnString);//建立数据库连接
    38.             PubsAdapter = new SqlDataAdapter(AdapterString, ConnPubs);//创建PubsAdapter数据读取器
    39.             IDAdapter = new SqlDataAdapter(IDString, ConnPubs);       //用于读取用户编号的读取器
    40.             PubsAdapter.Fill(PubsSet, "tb_User");            //填充PubsSet数据集
    41.             IDAdapter.Fill(PubsSet, "ID");                   //填充PubsSet数据集
    42.             DataTable PubsTable = PubsSet.Tables["tb_User"]!;//将数据写入PubsTable表
    43.             IDTable = PubsSet.Tables["ID"]!;                 //将数据写入ID表
    44.             IDArray = new string[IDTable.Rows.Count];        //为数组定义最大长度
    45.             dataGridView1.DataSource = PubsTable.DefaultView;//设置dataGridView1的数据源
    46.             for (int i = 0; i < IDTable.Rows.Count; i++)     //循环遍历数据表中的每一行数据
    47.             {
    48.                 for (int j = 0; j < IDTable.Columns.Count; j++)//循环遍历数据表中的每一列数据
    49.                 {
    50.                     IDArray[i] = IDTable.Rows[i][j].ToString()!;//将数据表中的数据添加至一个一维数组
    51.                 }
    52.             }
    53.         }
    54.  
    55.         #region 创建子窗体的CreateFrmChild方法
    56.         /// 
    57.         /// 设置子窗体的父窗体为当前窗体;
    58.         /// 实例化一个子窗体;
    59.         /// 在DataGridView控件中添加子窗体;
    60.         /// 显示子窗体;
    61.         /// 
    62.         public void CreateFrmChild()
    63.         {
    64.             Frm_Child BabyWindow = new()
    65.             {
    66.                 MdiParent = this,
    67.             };
    68.             dataGridView1.Controls.Add(BabyWindow);
    69.             BabyWindow.UpdateDataGridView += new EventHandler(BabyWindow_UpdateDataGridView!);
    70.             BabyWindow.Show();
    71.         }
    72.         /// 
    73.         /// 事件委托
    74.         /// 
    75.         void BabyWindow_UpdateDataGridView(object sender, EventArgs e)
    76.         {
    77.             if (Frm_Child.GlobalFlag == false)    //当单击删除按钮时
    78.             {
    79.                 if (ConnPubs!.State == ConnectionState.Closed) //当数据库处于断开状态时
    80.                 {
    81.                     ConnPubs.Open();              //打开数据库的连接
    82.                 }
    83.                 string AfreshString = "delete tb_User where userID=" + Frm_Child.DeleteID!.Trim();//定义一个删除数据的字符串
    84.                 PersonalInformation = new SqlCommand(AfreshString, ConnPubs); //执行删除数据库字段
    85.                 PersonalInformation.ExecuteNonQuery(); //执行SQL语句并返回受影响的行数
    86.                 ConnPubs.Close();                      //关闭数据库
    87.                 DisplayData();                         //显示数据库更新后的内容
    88.                 MessageBox.Show("数据删除成功！", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
    89.             }
    90.             else
    91.             {
    92.                 if (ConnPubs!.State == ConnectionState.Closed) //当数据库处于关闭状态时
    93.                 {
    94.                     ConnPubs.Open();    //打开数据库
    95.                 }
    96.                 string InsertString = "insert into tb_User values('" + Frm_Child.IdContent + "','" + Frm_Child.NameContent + "','" + Frm_Child.PhoneContent + "','" + Frm_Child.AddressContent + "')";//定义一个插入数据的字符串变量
    97.                 PersonalInformation = new SqlCommand(InsertString, ConnPubs);//执行插入数据库字段
    98.                 PersonalInformation.ExecuteNonQuery();          //执行SQL语句并返回受影响的行数
    99.                 ConnPubs.Close();        //关闭数据库
    100.                 DisplayData();           //显示更新后的数据
    101.                 MessageBox.Show("数据添加成功！", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
    102.             }
    103.         }
    104.         #endregion
    105.  
    106.         #region 用于读取数据库的DisplayData方法
    107.         public void DisplayData()
    108.         {
    109.             PubsSet.Clear();
    110.             ConnPubs = new SqlConnection(ConnString); 
    111.             string DisplayString = "select userId as 编号,userName as 姓名 ,phone as 电话,address as 住址 from tb_User";//定义读取数据库的字段
    112.             SqlDataAdapter PersonalAdapter = new(DisplayString, ConnPubs);    //定义一个读取数据库数据的读取器
    113.             PersonalAdapter.Fill(PubsSet, "tb_User");                                            //向表DisplayTable中填充数据
    114.             dataGridView1.DataSource = PubsSet.Tables["tb_User"]!.DefaultView; //设定DataGridView控件的数据源
    115.         }
    116.         #endregion
    117.         /// 
    118.         /// 添加或删除记录
    119.         /// 创建子窗体的CreateFrmChild方法
    120.         /// 
    121.         private void ToolStripMenuItem2_Click(object sender, EventArgs e)
    122.         {
    123.             if (flag == false)   //判断标识的值决定是否创建窗体
    124.             {
    125.                 CreateFrmChild();//创建子窗体
    126.             }
    127.             for (int i = 0; i < dataGridView1.Controls.Count; i++)                      //循环遍历DataGridView控件上的控件集
    128.             {
    129.                 if (dataGridView1.Controls[i].Name.Equals(BabyWindow.Name)) //当存在子窗体时
    130.                 {
    131.                     flag = true; //改变标识Flag的值
    132.                     break;       //退出循环体
    133.                 }
    134.             }
    135.         }
    136.         /// 
    137.         /// 退出
    138.         /// 
    139.         private void ToolStripMenuItem3_Click(object sender, EventArgs e)
    140.         {
    141.             Application.Exit();
    142.         }
    143.     }
    144. }

    4.实例的子窗体Frm_Child： 

    （1） Frm_Child.Designer.cs

    1. namespace _197
    2. {
    3.     partial class Frm_Child
    4.     {
    5.         /// 
    6.         /// Required designer variable.
    7.         /// 
    8.         private System.ComponentModel.IContainer components = null;
    9.  
    10.         /// 
    11.         /// Clean up any resources being used.
    12.         /// 
    13.         /// true if managed resources should be disposed; otherwise, false.
    14.         protected override void Dispose(bool disposing)
    15.         {
    16.             if (disposing && (components != null))
    17.             {
    18.                 components.Dispose();
    19.             }
    20.             base.Dispose(disposing);
    21.         }
    22.  
    23.         #region Windows Form Designer generated code
    24.  
    25.         /// 
    26.         /// Required method for Designer support - do not modify
    27.         /// the contents of this method with the code editor.
    28.         /// 
    29.         private void InitializeComponent()
    30.         {
    31.             groupBox1 = new GroupBox();
    32.             button2 = new Button();
    33.             button1 = new Button();
    34.             Record_Address = new TextBox();
    35.             Record_Phone = new TextBox();
    36.             Record_Name = new TextBox();
    37.             Record_ID = new TextBox();
    38.             label4 = new Label();
    39.             label3 = new Label();
    40.             label2 = new Label();
    41.             label1 = new Label();
    42.             groupBox2 = new GroupBox();
    43.             button3 = new Button();
    44.             comboBox1 = new ComboBox();
    45.             label5 = new Label();
    46.             groupBox1.SuspendLayout();
    47.             groupBox2.SuspendLayout();
    48.             SuspendLayout();
    49.             // 
    50.             // groupBox1
    51.             // 
    52.             groupBox1.Controls.Add(button2);
    53.             groupBox1.Controls.Add(button1);
    54.             groupBox1.Controls.Add(Record_Address);
    55.             groupBox1.Controls.Add(Record_Phone);
    56.             groupBox1.Controls.Add(Record_Name);
    57.             groupBox1.Controls.Add(Record_ID);
    58.             groupBox1.Controls.Add(label4);
    59.             groupBox1.Controls.Add(label3);
    60.             groupBox1.Controls.Add(label2);
    61.             groupBox1.Controls.Add(label1);
    62.             groupBox1.Location = new Point(12, 12);
    63.             groupBox1.Name = "groupBox1";
    64.             groupBox1.Size = new Size(270, 157);
    65.             groupBox1.TabIndex = 0;
    66.             groupBox1.TabStop = false;
    67.             groupBox1.Text = "添加信息";
    68.             // 
    69.             // button2
    70.             // 
    71.             button2.Location = new Point(187, 56);
    72.             button2.Name = "button2";
    73.             button2.Size = new Size(75, 23);
    74.             button2.TabIndex = 9;
    75.             button2.Text = "清空";
    76.             button2.UseVisualStyleBackColor = true;
    77.             button2.Click += Button2_Click;
    78.             // 
    79.             // button1
    80.             // 
    81.             button1.Location = new Point(187, 25);
    82.             button1.Name = "button1";
    83.             button1.Size = new Size(77, 23);
    84.             button1.TabIndex = 8;
    85.             button1.Text = "提交";
    86.             button1.UseVisualStyleBackColor = true;
    87.             button1.Click += Button1_Click;
    88.             // 
    89.             // Record_Address
    90.             // 
    91.             Record_Address.Location = new Point(72, 118);
    92.             Record_Address.Name = "Record_Address";
    93.             Record_Address.Size = new Size(100, 23);
    94.             Record_Address.TabIndex = 7;
    95.             Record_Address.TextChanged += Record_Address_TextChanged;
    96.             // 
    97.             // Record_Phone
    98.             // 
    99.             Record_Phone.Location = new Point(72, 87);
    100.             Record_Phone.Name = "Record_Phone";
    101.             Record_Phone.Size = new Size(100, 23);
    102.             Record_Phone.TabIndex = 6;
    103.             Record_Phone.TextChanged += Record_Phone_TextChanged;
    104.             // 
    105.             // Record_Name
    106.             // 
    107.             Record_Name.Location = new Point(72, 56);
    108.             Record_Name.Name = "Record_Name";
    109.             Record_Name.Size = new Size(100, 23);
    110.             Record_Name.TabIndex = 5;
    111.             Record_Name.TextChanged += Record_Name_TextChanged;
    112.             // 
    113.             // Record_ID
    114.             // 
    115.             Record_ID.Location = new Point(72, 25);
    116.             Record_ID.Name = "Record_ID";
    117.             Record_ID.Size = new Size(100, 23);
    118.             Record_ID.TabIndex = 4;
    119.             Record_ID.TextChanged += Record_ID_TextChanged;
    120.             // 
    121.             // label4
    122.             // 
    123.             label4.AutoSize = true;
    124.             label4.Location = new Point(11, 118);
    125.             label4.Name = "label4";
    126.             label4.Size = new Size(44, 17);
    127.             label4.TabIndex = 3;
    128.             label4.Text = "地址：";
    129.             // 
    130.             // label3
    131.             // 
    132.             label3.AutoSize = true;
    133.             label3.Location = new Point(11, 87);
    134.             label3.Name = "label3";
    135.             label3.Size = new Size(44, 17);
    136.             label3.TabIndex = 2;
    137.             label3.Text = "电话：";
    138.             // 
    139.             // label2
    140.             // 
    141.             label2.AutoSize = true;
    142.             label2.Location = new Point(11, 56);
    143.             label2.Name = "label2";
    144.             label2.Size = new Size(44, 17);
    145.             label2.TabIndex = 1;
    146.             label2.Text = "姓名：";
    147.             // 
    148.             // label1
    149.             // 
    150.             label1.AutoSize = true;
    151.             label1.Location = new Point(11, 25);
    152.             label1.Name = "label1";
    153.             label1.Size = new Size(44, 17);
    154.             label1.TabIndex = 0;
    155.             label1.Text = "编号：";
    156.             // 
    157.             // groupBox2
    158.             // 
    159.             groupBox2.Controls.Add(button3);
    160.             groupBox2.Controls.Add(comboBox1);
    161.             groupBox2.Controls.Add(label5);
    162.             groupBox2.Location = new Point(12, 175);
    163.             groupBox2.Name = "groupBox2";
    164.             groupBox2.Size = new Size(270, 54);
    165.             groupBox2.TabIndex = 1;
    166.             groupBox2.TabStop = false;
    167.             groupBox2.Text = "删除信息";
    168.             // 
    169.             // button3
    170.             // 
    171.             button3.Location = new Point(187, 24);
    172.             button3.Name = "button3";
    173.             button3.Size = new Size(75, 23);
    174.             button3.TabIndex = 2;
    175.             button3.Text = "删除";
    176.             button3.UseVisualStyleBackColor = true;
    177.             button3.Click += Button3_Click;
    178.             // 
    179.             // comboBox1
    180.             // 
    181.             comboBox1.FormattingEnabled = true;
    182.             comboBox1.Location = new Point(72, 24);
    183.             comboBox1.Name = "comboBox1";
    184.             comboBox1.Size = new Size(100, 25);
    185.             comboBox1.TabIndex = 1;
    186.             // 
    187.             // label5
    188.             // 
    189.             label5.AutoSize = true;
    190.             label5.Location = new Point(11, 30);
    191.             label5.Name = "label5";
    192.             label5.Size = new Size(44, 17);
    193.             label5.TabIndex = 0;
    194.             label5.Text = "编号：";
    195.             // 
    196.             // Frm_Child
    197.             // 
    198.             AutoScaleDimensions = new SizeF(7F, 17F);
    199.             AutoScaleMode = AutoScaleMode.Font;
    200.             ClientSize = new Size(294, 241);
    201.             Controls.Add(groupBox2);
    202.             Controls.Add(groupBox1);
    203.             MaximizeBox = false;    //最大化按钮没有意义
    204.             Name = "Frm_Child";
    205.             StartPosition = FormStartPosition.CenterScreen;
    206.             Text = "子窗体";
    207.             FormClosing += Frm_Child_FormClosing;
    208.             Load += Frm_Child_Load;
    209.             groupBox1.ResumeLayout(false);
    210.             groupBox1.PerformLayout();
    211.             groupBox2.ResumeLayout(false);
    212.             groupBox2.PerformLayout();
    213.             ResumeLayout(false);
    214.         }
    215.  
    216.         #endregion
    217.  
    218.         private GroupBox groupBox1;
    219.         private TextBox Record_Address;
    220.         private TextBox Record_Phone;
    221.         private TextBox Record_Name;
    222.         private TextBox Record_ID;
    223.         private Label label4;
    224.         private Label label3;
    225.         private Label label2;
    226.         private Label label1;
    227.         private GroupBox groupBox2;
    228.         private Button button2;
    229.         private Button button1;
    230.         private Button button3;
    231.         private ComboBox comboBox1;
    232.         private Label label5;
    233.     }
    234. }

    （2）Frm_Child.cs

    1. // 本实例仅可创建一个窗口:
    2. // 最大化后没有实际意义，因此关闭MaximizeBox属性值为False
    3. namespace _197
    4. {
    5.     public partial class Frm_Child : Form
    6.     {
    7.         #region 变量的声明
    8.         public event EventHandler? UpdateDataGridView = null;//定义一个处理更新DataGridView控件内容的方法
    9.         private static string? deleteID;        //定义一个表示删除数据编号的字符串
    10.         private static string? idContent;       //该变量用来存储数据编号
    11.         private static string? nameContent;     //该变量用来存储姓名
    12.         private static string? phoneContent;    //该变量用来存储电话
    13.         private static string? addressContent;  //该变量用来存储住址
    14.         private static bool globalFlag;         //该变量用来标识是否创建新的子窗体
    15.  
    16.         public static string? DeleteID { get => deleteID; set => deleteID = value; }
    17.         public static string? IdContent { get => idContent; set => idContent = value; }
    18.         public static string? NameContent { get => nameContent; set => nameContent = value; }
    19.         public static string? PhoneContent { get => phoneContent; set => phoneContent = value; }
    20.         public static string? AddressContent { get => addressContent; set => addressContent = value; }
    21.         public static bool GlobalFlag { get => globalFlag; set => globalFlag = value; }
    22.         #endregion
    23.  
    24.         public Frm_Child()
    25.         {
    26.             InitializeComponent();
    27.         }
    28.         /// 
    29.         /// 添加
    30.         /// 
    31.         private void Button1_Click(object? sender, EventArgs e)
    32.         {
    33.             GlobalFlag = true;                          //设定标识的值为true
    34.             if (!(comboBox1.Items.Equals(idContent)))   //当Combobox控件中不存在将添加的信息时
    35.             {
    36.                 comboBox1.Items.Add(idContent!);        //在Combobox控件中添加一条记录
    37.             }
    38.             UpdateData();
    39.         }
    40.         /// 
    41.         /// 清空
    42.         /// 
    43.         private void Button2_Click(object? sender, EventArgs e)
    44.         {
    45.             Record_ID.Clear();      //清空编号文本框中的内容
    46.             Record_Name.Clear();    //清空姓名文本框中的内容
    47.             Record_Phone.Clear();   //清空电话号码文本框中的内容
    48.             Record_Address.Clear(); //清空居住地址文本框中的内容
    49.             Record_ID.Focus();      //设定当前鼠标的焦点在编号文本框中
    50.         }
    51.         /// 
    52.         /// 删除
    53.         /// 
    54.         private void Button3_Click(object? sender, EventArgs e)
    55.         {
    56.             GlobalFlag = false;             //设定全局变量表示为false
    57.             if (comboBox1.Items.Count > 1)  //当ComboBox中剩不小于2条内容时
    58.             {
    59.                 DeleteID = comboBox1.SelectedItem!.ToString();  //将选中项转化为int型
    60.                 if (comboBox1.Items.Count != 0)                 //当ComboBox中剩1条内容时
    61.                 {
    62.                     comboBox1.Items.Remove(comboBox1.SelectedItem);
    63.                     comboBox1.SelectedIndex = 0;
    64.                 }
    65.             }
    66.             UpdateData(); 
    67.         }
    68.         /// 
    69.         /// 保存新添加记录的编号
    70.         /// 
    71.         private void Record_ID_TextChanged(object? sender, EventArgs e)
    72.         {
    73.             idContent = Record_ID.Text;
    74.         }
    75.         /// 
    76.         /// 保存填入的姓名
    77.         /// 
    78.         private void Record_Name_TextChanged(object? sender, EventArgs e)
    79.         {
    80.             nameContent = Record_Name.Text;
    81.         }
    82.         /// 
    83.         /// 保存填入的电话号码
    84.         /// 
    85.         private void Record_Phone_TextChanged(object? sender, EventArgs e)
    86.         {
    87.             phoneContent = Record_Phone.Text;
    88.         }
    89.         /// 
    90.         /// 保存填入的地址信息
    91.         /// 
    92.         private void Record_Address_TextChanged(object? sender, EventArgs e)
    93.         {
    94.             addressContent = Record_Address.Text;
    95.         }
    96.         /// 
    97.         /// 循环遍历数组中的每一个元素,向Combobox控件中添加内容
    98.         /// 默认设定当前选中项的索引为0
    99.         /// 
    100.         private void Frm_Child_Load(object? sender, EventArgs e)
    101.         {
    102.             for (int i = 0; i < Frm_Main.IDArray!.Length; i++)
    103.             {
    104.                 comboBox1.Items.Add(Frm_Main.IDArray[i].ToString());
    105.                 comboBox1.SelectedIndex = 0;
    106.             }
    107.         }
    108.         /// 
    109.         /// 设定该值为false表示可以创建新窗体
    110.         /// 
    111.         private void Frm_Child_FormClosing(object? sender, FormClosingEventArgs e)
    112.         {
    113.             Frm_Main.Flag = false; 
    114.         }
    115.        
    116.         /// 
    117.         /// 更新DataGridView控件中的内容
    118.         /// 
    119.         protected void UpdateData()
    120.         {
    121.             UpdateDataGridView?.Invoke(this, EventArgs.Empty);
    122.         }
    123.     }
    124. }

    5.生成效果

    （1）生成

     

    （2）添加

     

    （3）添加后

     

    （4）清空

     

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  • 原文地址：https://blog.csdn.net/wenchm/article/details/138191594