1.直接修改, 失败引发异常.
namespace Test
{ public partial class frmVisitControl : Form { public frmVisitControl() { InitializeComponent(); }private void SetLabelText()
{ label1.Text = "Hello"; } private void btnVisitLabel_Click(object sender, EventArgs e) { //以下这句将引发InvalidOperationException Thread th = new Thread(SetLabelText); th.Start(); } }}
2.使用代理, 调用UI控件的invoke方法修改, 成功.
namespace Test
{ public partial class frmVisitControl : Form { public frmVisitControl() { InitializeComponent(); }private void SetLabelText()
{ label1.Text = "Hello"; }delegate void delabc();
public void setText() { delabc a = SetLabelText; label1.Invoke(a, null); } private void btnVisitLabel_Click(object sender, EventArgs e) { Thread th = new Thread(setText); th.Start(); } }}3.使用c#2.0提供的匿名(代理)方法,省一点代码.
namespace Test
{ public partial class frmVisitControl : Form { public frmVisitControl() { InitializeComponent(); }delegate void delabc();
public void setText() { delabc a = delegate() { label1.Text = "Hello"; };label1.BeginInvoke(a);
} private void btnVisitLabel_Click(object sender, EventArgs e) { //以下这句将引发InvalidOperationException Thread th = new Thread(setText); th.Start(); } }}
4.使用c#3.5, 4.0中的Action委托, 连代理声明那句都省了.
namespace Test
{ public partial class frmVisitControl : Form { public frmVisitControl() { InitializeComponent(); }public void setText()
{ Action a = delegate() { label1.Text = "Hello"; }; label1.BeginInvoke(a); }private void btnVisitLabel_Click(object sender, EventArgs e)
{ Thread th = new Thread(setText); th.Start(); } }}注释：Action委托，用来封装一个方法，该方法不具有参数并且不返回值。 与之对应的是Func委托，它可以有返回值．