C#练习2、窗体传值

常用方法有： 一、通过委托（子窗体传值给父窗体） 效果图： Form1类中代码：

public partial class Form1 : Form { public Form1() { InitializeComponent(); } public void ShowText(string strV) { this.textBox1.Text = strV; } private void button1_Click(object sender, EventArgs e) { Form2 form2 = new Form2(ShowText); form2.ShowDialog(); } }

Form2类中代码：

public delegate void DelSendValue(string str); public partial class Form2 : Form { //委托类型字段，存储Form1传送过来的函数 private DelSendValue delMethod; //------ //public delegate void GetTextHandler(string text); public Form2(DelSendValue del) { this.delMethod = del; InitializeComponent(); } private void Form2_Load(object sender, EventArgs e) { } //通过委托传值给窗体1，实际上运行的是窗体1的ShowText方法 private void button1_Click(object sender, EventArgs e) { if (delMethod != null) { this.delMethod(this.textBox1.Text.Trim()); } } }

二、【通过Form类构造方法的重载传参】父窗体传值给子窗体

Form1类中代码：

public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { Form2 f2 = new Form2(textBox1.Text); f2.ShowDialog(); } }

Form2类中代码：

public partial class Form2 : Form { public Form2() { InitializeComponent(); } public Form2(string str) { InitializeComponent(); textBox1.Text = str; // } }

三、通过事件

form1代码

public partial class Form1 : Form { public Form1() { InitializeComponent(); } //private void button1_Click(object sender, EventArgs e) //{ // Form2 f2 = new Form2(); // f2.ChangeText += new ChangeTextHandler(Change_Text); // // f2.ShowDialog(); //} //private void Change_Text(string str) //{ // textBox1.Text = str; //} private void button1_Click(object sender, EventArgs e) { Form2 f2 = new Form2(); f2.ChangeText += (str) => textBox1.Text = str; //用lambda表达式实现 f2.ShowDialog(); } private void textBox1_TextChanged(object sender, EventArgs e) { } }

form2代码

//public delegate void ChangeTextHandler(string str); //定义委托 public partial class Form2 : Form { public Form2() { InitializeComponent(); } //public event ChangeTextHandler ChangeText; //定义事件 public Action<string> ChangeText; //之前的定义委托和定义事件由这一句代替 private void button1_Click(object sender, EventArgs e) { if (ChangeText != null) //判断事件是否为空 { ChangeText(textBox2.Text); //执行事件 this.Close(); } } }