Question

C# 窗体控件问题，text属性更改后不显示。

代码如下：
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Threading;

namespace 生产者_消费者
{
public partial class Form1 : Form
{
private object thisLock = new object();
private Queue<string> list = new Queue<String>();

Thread threadPrint;
Thread threadDownload ;

private int max = 5;//仓库最大为5，可储存5个商品。
private int count = 0;

private static Form1 form = new Form1();

public Form1()
{
InitializeComponent();
}

private void startProduct_Click(object sender, EventArgs e)
{
if (this.startProduct.Text == "开始生产")
{
threadPrint = new Thread(new ThreadStart(form.product));
threadPrint.Start();

this.startProduct.Text = "停止生产";
}else if (this.startProduct.Text == "停止生产")
{
threadPrint.Suspend();
this.startProduct.Text = "继续生产";
}else if (this.startProduct.Text == "继续生产")
{
threadPrint.Resume();
this.startProduct.Text = "停止生产";
}

}

private void startConsume_Click(object sender, EventArgs e)
{
if (this.startConsume.Text == "开始消费")
{
threadDownload = new Thread(new ThreadStart(form.consume));
threadDownload.Start();

this.startConsume.Text = "停止消费";
}else if (this.startConsume.Text == "停止消费")
{
threadDownload.Suspend();
this.startConsume.Text = "继续消费";
}else if (this.startConsume.Text == "继续消费")
{
threadDownload.Resume();
this.startConsume.Text = "停止消费";
}
}

public void product()//生产者。
{
while (true)
{
if (count < max)
{
lock (this)
{
list.Enqueue("第" + (count + 1) + "个商品。");
count ++;
MessageBox.Show("生产者:生产第" + count + "个");
// this.productShow.Text = "生产者:生产第" + count + "个";
//此处控件text属性更改后不显示。 为什么？
}
}
Thread.Sleep(2000);
}
}
后面还有代码，但百度不让贴上来了。

Answer 1

不要在线程里访问UI线程创建的控件, 用Invoke

public void product()//生产者。
{
while (true)
{
if (count < max)
{
lock (this)
{
list.Enqueue("第" + (count + 1) + "个商品。");
count++;
//MessageBox.Show("生产者:生产第" + count + "个");
// this.productShow.Text = "生产者:生产第" + count + "个";
Showproduct(count);
}
}
Thread.Sleep(2000);
}
}

private delegate void ShowproductDelegate(int count);
private void Showproduct(int count)
{
if (this.InvokeRequired)
{
this.BeginInvoke(new ShowproductDelegate(Showproduct), new object[] { count });
}
else
{
this.productShow.Text = "生产者:生产第" + count + "个";
}
}