C# 带输入参数的 Control.Invoke
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Control.Invoke with input Parameters
提问by Adam Haile
From what I've found in C#, the Control.Invoke method requires that you use a delegate with no input parameters. Is there any way around this? I would like to invoke a method to update the UI from another thread and pass to string parameters to it.
根据我在 C# 中的发现，Control.Invoke 方要求您使用没有输入参数的委托。有没有办解决？我想调用一个方来从另一个线程更新 UI 并将字符串参数传递给它。
采纳答案by Samuel
Which version of C# are you using? If you are using C#3.5 you can use closures to avoid passing in parameters.
您使用的是哪个版本的 C#？如果您使用的是 C#3.5，您可以使用闭包来避免传入参数。
使用 C#3.5public static class ControlExtensions
{
public static TResult InvokeEx<TControl, TResult>(this TControl control,
Func<TControl, TResult> func)
where TControl : Control
{
return control.InvokeRequired
? (TResult)control.Invoke(func, control)
: func(control);
}
public static void InvokeEx<TControl>(this TControl control,
Action<TControl> func)
where TControl : Control
{
control.InvokeEx(c => { func(c); return c; });
}
public static void InvokeEx<TControl>(this TControl control, Action action)
where TControl : Control
{
control.InvokeEx(c => action());
}
}
Safely invoking code now becomes trivial.
安全调用代码现在变得微不足道。
this.InvokeEx(f => f.label1.Text = "Hello World");
this.InvokeEx(f => this.label1.Text = GetLabelText("HELLO_WORLD", var1));
this.InvokeEx(() => this.label1.Text = DateTime.Now.ToString());
使用 C#2.0，它变得不那么琐碎
public class MyForm : Form
{
private delegate void UpdateControlTextCallback(Control control, string text);
public void UpdateControlText(Control control, string text)
{
if (control.InvokeRequired)
{
control.Invoke(new UpdateControlTextCallback(UpdateControlText), control, text);
}
else
{
control.Text = text;
}
}
}
Using it simple, but you have to define more callbacks for more parameters.
使用起来很简单，但是你必须为更多的参数定义更多的回调。
this.UpdateControlText(label1, "Hello world");
回答by Sorin Comanescu
I think Samuel's (excellent) approach can be pushed even more:
我认为塞缪尔 (Samuel) 的（优秀）方可以进一步推广：
Extension Method:
扩展方：
public static void ExecuteAsync<TControl>(this TControl control, Action action)
where TControl : Control
{
new Thread(() =>
{
control.Invoke(action);
})
.Start();
}
Form code:
表格代码：
private void doStuff()
{
this.ExecuteAsync(() =>
{
// Do your stuff in a separate thread
// but having full access to local or instance variables.
// No (visible) threading code needs to be used here.
});
}
回答by Tim
As Luke says, use Control.Invoke like this...
正如卢克所说，像这样使用 Control.Invoke ......
For example in a form:
例如在一个表格中：
public delegate void DelegatePassMessages(string name, int value);
public DelegatePassMessages passMessage;
In the contructor:
在构造函数中：
passMessage = new DelegatePassMessages (this.MessagesIn);
Then the MessagesIn function to receive data:
然后是 MessagesIn 函数来接收数据：
public void MessagesIn(string name, int value)
{
}
Then to pass data to your form:
然后将数据传递给您的表单：
formName.Invoke(formName.passMessage, new Object[] { param1, param2});
回答by gsharp
Found an elegant method for .net 2.0 with anonymous methods wrapped in a MethodInvoker Delegate. That way is no need to define own delegates all the time. Example:
找到了一种适用于 .net 2.0 的优雅方，其中匿名方包含在 MethodInvoker Delegate 中。这样就不需要一直定义自己的委托了。例子：
private void InitUI(Guid id, string typename)
{
MethodInvoker inv = delegate{tvMatrix.Nodes[0].Nodes.Add(id.ToString(), typename);};
tvMatrix.Invoke(inv);
}
回答by Makah
Why not
为什么不
tvMatrix.Invoke((MethodInvoker) (() => {
tvMatrix.Nodes[0].Nodes.Add(id.ToString(), typename);
}));
回答by Denis T
Some more possibilities:
还有一些可能性：
this.Invoke(new MethodInvoker(() => this.DoSomething(param1, param2)));
or
或者
this.Invoke(new Action(() => this.DoSomething(param1, param2)));
or even
甚至
this.Invoke(new Func<YourType>(() => this.DoSomething(param1, param2)));
where the first option is the best one, because MethodInvoker is concepted for that purposes and has a better performance.
其中第一个选项是最好的，因为 MethodInvoker 是为此目的而设计的，并且具有更好的性能。
回答by Latency
Here ya go using lambda expressions with the Invoke() extension + an input parameter.
在这里，您可以使用带有 Invoke() 扩展 + 输入参数的 lambda 表达式。
Using: action(STARS db)
使用：动作(STARS db)
_ccb.GetImagerFRU_PartNbr().Invoke(new Action<STARS>(dbase => _ccb.GetImagerFRU_PartNbr().Text = dbase.PartNumber(serial) ?? String.Empty), db);
回答by focus jung
private void ppTrace(string tv)
{
if (_Txb1.InvokeRequired)
{
_Txb1.Invoke((Action<string>)ppTrace, tv);
}
else
{
_Txb1.AppendText(tv + Environment.NewLine);
}
}
