Cross-thread operation not valid: Control ‘progressBar1′ accessed from a thread other th

<div class=" article-meta>當您試圖從單獨的線程更新一個win form時，您將得到如下錯誤資訊： 
"Cross-thread operation not valid: Control 'progressBar1' accessed from a thread other than the thread it was created on."  本文將介紹如何處理此錯誤：

問題：

 重現該錯誤, 添加一個 progress bar 控制項 (progressbar1) 以及一個  button(btnStart)到您的表單上：.

private void btnStart_Click(object sender, EventArgs e)
{
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;

System.Threading.Thread t1 = new System.Threading.Thread(startProgress);
t1.Start();
}
void startProgress()
{
for (int i = 0; i {
progressBar1.Value = i; //You will get error at this line
System.Threading.Thread.Sleep(100);
}
}

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解決方案：

private void btnStart_Click(object sender, EventArgs e)
{
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;

System.Threading.Thread t1 = new System.Threading.Thread(startProgress);
t1.Start();
}
void startProgress()
{
for (int i = 0; i {
SetControlPropertyValue(progressBar1, "value", i); //This is a thread safe method
System.Threading.Thread.Sleep(100);
}
}

delegate void SetControlValueCallback(Control oControl, string propName, object propValue);
private void SetControlPropertyValue(Control oControl, string propName, object propValue)
{
if (oControl.InvokeRequired)
{
SetControlValueCallback d = new SetControlValueCallback(SetControlPropertyValue);
oControl.Invoke(d, new object[] { oControl, propName, propValue });
}
else
{
Type t = oControl.GetType();
PropertyInfo[] props = t.GetProperties();
foreach (PropertyInfo p in props)
{
if (p.Name.ToUpper() == propName.ToUpper())
{
p.SetValue(oControl, propValue, null);
}
}
}
}

您可以通過該解決方案來處理所有的WIndows 控制項. 您所要做的是, 從上方的代碼中copy SetControlValueCallback delegate 以及SetControlPropertyValue 函數 function.

例如您想設定一個 label的內容, 使用SetControlPropertyValueSetControlPropertyValue(Label1, "Text", i.ToString()); 

請確認您所應用的屬性的實值型別.在上面的Demo中 Text 是一個 string 屬性. 這就是我為什麼將其轉換為String。