[C# 学习]窗体间调用控件

一、方法1：

假如有两个窗体，Form_A和Form_B，每个窗体里都有一个按键，Button_A和Button_B，要实现单击Button_A显示窗体B，那么窗体A中Buttom_A的单击事件的程序应该是：

private void button_A_Click(object sender, EventArgs e)
{
    Form_B  f = new Form_B();
    f.Show();
}

如果希望单击窗体B中的按键Button_B，实现改变窗体A的背景色，那么你需要做：

1. Form_B 窗体的Class里添加如下代码：

public Form_A fb;
public Form_B(Form_A  f)
{
    InitializeComponent();
    fb = f;
}
 
private void button_B_Click(object sender, EventArgs e)
{
    fb.BackColor = Color.Brown;
}

2. Form_A窗体中的Button_A单击事件变成：

private void button_A_Click(object sender, EventArgs e)
{
    Form_B f = new Form_B(this);
    f.Show();
}

完整程序如下

Form_A：

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 formExam
{
    public partial class Form_A : Form
    {
        public Form_A()
        {
            InitializeComponent();
        }
 
        private void Button_A_Click(object sender, EventArgs e)
        {
            Form_B f = new Form_B(this);
            f.Show();
        }
 
        private void Form_A_Load(object sender, EventArgs e)
        {
 
        }
    }
}

Form_B:

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 formExam
{
    public partial class Form_B : Form
    {
        public Form_A fb;
        public Form_B(Form_A f)
        {
            InitializeComponent();
            fb = f;
        }
 
        private void Button_B_Click(object sender, EventArgs e)
        {
            fb.BackColor = Color.Brown;
        }
    }
}

二、方法2：通过委托实现

1. 在Form_B的Class外定义一个委托类型

 public delegate void ChangeFormColor();

2. 在Form_B的Class内定义委托的方法

public event ChangeFormColor ChangeColor;

3. Button_B单击事件为

private void Button_B_Click(object sender, EventArgs e)
{
    ChangeColor();
}

4. Form_A中的单击事件为

private void Button_A_Click(object sender, EventArgs e)
{
    Form_B f = new Form_B();
    f.ChangeColor += new ChangeFormColor(f_ChangeColor);
    f.Show();
}

5. 编写改变Form_A 背景色的方法

void f_ChangeColor()
{
    this.BackColor = Color.Brown;
}

完整程序如下：

Form_A:

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 formExam
{
    public partial class Form_A : Form
    {
        public Form_A()
        {
            InitializeComponent();
        }
 
        private void Button_A_Click(object sender, EventArgs e)
        {
            Form_B f = new Form_B();
            f.ChangeColor += new ChangeFormColor(f_ChangeColor);
            f.Show();
        }
 
        void f_ChangeColor()
        {
            this.BackColor = Color.Brown;
        }
    }
}

Form_B:

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 formExam
{
    public delegate void ChangeFormColor();
 
    public partial class Form_B : Form
    {
        public event ChangeFormColor ChangeColor;
        public Form_B()
        {
            InitializeComponent();
        }
 
        private void Button_B_Click(object sender, EventArgs e)
        {
            ChangeColor();
        }
    }
}