C# 学习代理事件的简单快速示例
我是这个话题的新手。我创建了一个c#win表单。在这个表单中,我有两个文本框和一个标签。我要做的是创建一个委托事件来跟踪文本框的更改,并将C# 学习代理事件的简单快速示例,c#,winforms,events,delegates,C#,Winforms,Events,Delegates,我是这个话题的新手。我创建了一个c#win表单。在这个表单中,我有两个文本框和一个标签。我要做的是创建一个委托事件来跟踪文本框的更改,并将textbox1和textbox2中的两个数字相加。标签将自动显示结果。希望有人能给我举个例子,非常感谢!我现在有些东西 events.cs: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Project3 {
textbox1
和textbox2
中的两个数字相加。标签将自动显示结果。希望有人能给我举个例子,非常感谢!我现在有些东西
events.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Project3
{
public delegate void Calculate(int obj1, int obj2);
public class events
{
int result;
public int Add(int x, int y)
{
result = x + y;
return result;
}
}
}
表格1.cs:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace Project3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
label1.Text ="";
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
}
}
}
如果您只想了解如何将结果委派到标签中,并了解
委派
和事件
,以下是一个示例,您可能希望尝试并分析该示例以供学习:
示例1:
public delegate int CalculateEventHandler(object obj1, object obj2);
public partial class Form1 : Form
{
public event CalculateEventHandler Calculate;
private string OnCalculate(string text1, string text2)
{
string result = "0";
if (this.Calculate != null)
{
result = this.Calculate(this.textBox1.Text, this.textBox2.Text).ToString();
}
return result;
}
public Form1()
{
this.InitializeComponent();
this.InitializeEvent();
}
private void InitializeEvent()
{
this.Calculate += Form1_Calculate;
}
private int Form1_Calculate(object obj1, object obj2)
{
int a = 0;
int b = 0;
int.TryParse(obj1.ToString(), out a);
int.TryParse(obj2.ToString(), out b);
return a + b;
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
this.label1.Text = OnCalculate(this.textBox1.Text, this.textBox2.Text);
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
this.label1.Text = OnCalculate(this.textBox1.Text, this.textBox2.Text);
}
}
示例2:
public delegate int CalculateEventHandler(object obj1, object obj2);
public partial class Form1 : Form
{
public event CalculateEventHandler Calculate;
private string OnCalculate(string text1, string text2)
{
string result = "0";
if (this.Calculate != null)
{
result = this.Calculate(this.textBox1.Text, this.textBox2.Text).ToString();
}
return result;
}
public Form1()
{
this.InitializeComponent();
this.InitializeEvent();
}
private void InitializeEvent()
{
this.Calculate += Form1_Calculate;
}
private int Form1_Calculate(object obj1, object obj2)
{
int a = 0;
int b = 0;
int.TryParse(obj1.ToString(), out a);
int.TryParse(obj2.ToString(), out b);
return a + b;
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
this.label1.Text = OnCalculate(this.textBox1.Text, this.textBox2.Text);
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
this.label1.Text = OnCalculate(this.textBox1.Text, this.textBox2.Text);
}
}
表格1.cs
Event.cs
注:以上示例绝不是计算两个值的好方法,这只是一个示例。这种方法的缺点会导致您在某种程度上编写出“意大利面条”代码,并来回返回逻辑所在的位置。有一个简单的解决方案
private void textBox1_TextChanged(object sender, EventArgs e)
{
try
{
if (textBox2.Text == string.Empty)
{
//textBox2.Text = (0).ToString();
label1.Text = ( Convert.ToInt32(textBox1.Text)).ToString();
}
else if (textBox1.Text == string.Empty)
{
label1.Text = (Convert.ToInt32(textBox2.Text)).ToString();
}
else
{
label1.Text = (Convert.ToInt32(textBox1.Text) + Convert.ToInt32(textBox2.Text)).ToString();
}
}
catch (Exception e3)
{
MessageBox.Show(e3.Message);
}
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
try
{
if (textBox2.Text == string.Empty)
{
//textBox2.Text = (0).ToString();
label1.Text = (Convert.ToInt32(textBox1.Text)).ToString();
}
else if (textBox1.Text == string.Empty)
{
label1.Text = (Convert.ToInt32(textBox2.Text)).ToString();
}
else
{
label1.Text = (Convert.ToInt32(textBox1.Text) + Convert.ToInt32(textBox2.Text)).ToString();
}
}
catch (Exception e3)
{
MessageBox.Show(e3.Message);
}
}
您不需要创建自己的委托或定义新事件。只需在
TextChanged
处理程序中编写代码。@AVD我知道,但我尽量不使用给定的处理程序。谢谢!这是一个很好的例子!但你们能把事件类和表单类分开吗?我想要两个类。你可以(参见编辑的示例)。但同样,这只是为了学习,有更好的方法来处理TextChanged
事件中的计算。请添加一些文本,解释您正在做什么以及为什么要这样做
private void textBox1_TextChanged(object sender, EventArgs e)
{
try
{
if (textBox2.Text == string.Empty)
{
//textBox2.Text = (0).ToString();
label1.Text = ( Convert.ToInt32(textBox1.Text)).ToString();
}
else if (textBox1.Text == string.Empty)
{
label1.Text = (Convert.ToInt32(textBox2.Text)).ToString();
}
else
{
label1.Text = (Convert.ToInt32(textBox1.Text) + Convert.ToInt32(textBox2.Text)).ToString();
}
}
catch (Exception e3)
{
MessageBox.Show(e3.Message);
}
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
try
{
if (textBox2.Text == string.Empty)
{
//textBox2.Text = (0).ToString();
label1.Text = (Convert.ToInt32(textBox1.Text)).ToString();
}
else if (textBox1.Text == string.Empty)
{
label1.Text = (Convert.ToInt32(textBox2.Text)).ToString();
}
else
{
label1.Text = (Convert.ToInt32(textBox1.Text) + Convert.ToInt32(textBox2.Text)).ToString();
}
}
catch (Exception e3)
{
MessageBox.Show(e3.Message);
}
}