标签：tar rms service click csharp his art ace 传递
1）目标
父窗口与子窗口都有1个Button和1个Label。
目标1：单击父窗口的Button，子窗口的Label将显示父窗口传来的值。
目标2：单击子窗口的Button，父窗口的Label将显示子窗口传来的值。
2）父窗口代码
using System;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace WindowsFormsApp5
{
public delegate void ShowMessageService(string msg);
public partial class FormMain : Form
{
private FormChild childForm = new FormChild();
public FormMain()
{
InitializeComponent();
}
private void FormMain_Load(object sender, EventArgs e)
{
childForm.showMessageChild = new ShowMessageService(UpdateLabel);
childForm.Show();
}
public async void UpdateLabel(string msg)
{
await Task.Delay(2000);
this.label1.Text = msg;
}
private void button1_Click(object sender, EventArgs e)
{
ShowMessageService sms = new ShowMessageService(childForm.UpdateLabel);
this.BeginInvoke(sms, "Message from FormMain");
}
}
}
3）子窗口代码
using System;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace WindowsFormsApp5
{
public partial class FormChild : Form
{
public ShowMessageService showMessageChild;
public FormChild()
{
InitializeComponent();
}
public async void UpdateLabel(string msg)
{
await Task.Delay(2000);
this.label1.Text = msg;
}
private void button1_Click(object sender, EventArgs e)
{
this.BeginInvoke(showMessageChild, "Message from FormChild");
}
}
}
4）解释
4.1)定义委托
public delegate void ShowMessageService(string msg);
4.2）父窗口向子窗口传递消息
①由于父窗口拥有子窗口对象，所以直接利用子窗口的方法来创建委托对象，然后用this.BeginInvoke进行异步调用。
private void button1_Click(object sender, EventArgs e)
{
ShowMessageService sms = new ShowMessageService(childForm.UpdateLabel);//定义委托对象，指向子窗口的UpdateLabel方法。
this.BeginInvoke(sms, "Message from FormMain"); //执行的是子窗口的UpdateLabel方法
}
4.3）子窗口向父窗口传递消息
①子窗口声明委托对象
public partial class FormChild : Form
{
public ShowMessageService showMessageChild;//声明
}
②在主窗口给委托对象赋值。
public partial class FormMain : Form
{
private FormChild childForm = new FormChild();
private void FormMain_Load(object sender, EventArgs e)
{
childForm.showMessageChild = new ShowMessageService(UpdateLabel); //子窗口的委托对象指向父窗口的UpdateLabel方法。
childForm.Show();
}
}
③子窗口用this.BeginInvoke进行异步调用。
private void button1_Click(object sender, EventArgs e)
{
this.BeginInvoke(showMessageChild, "Message from FormChild");
}
标签：tar rms service click csharp his art ace 传递
原文地址：https://www.cnblogs.com/wyvern0618/p/9442381.html
