wpf 如何使用 InvokeRequired
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How to use InvokeRequired
提问by iAteABug_And_iLiked_it
I have the code below in vb.net, and I am converting it to c#. EDITEdited out irrelevant code.
我在 vb.net 中有下面的代码，我正在将其转换为 c#。 编辑编辑掉不相关的代码。
but I am stuck at the one with InvokeRequired. I have added a reference to System.Windows.Formsand still the code completion doesn't show InvokeRequired. The listview is on a separate thread to the one I am calling it from, and I need to get around that using Invoke. Can you please tell me what am I missing?
Thank you.
但我被困在了InvokeRequired. 我已经添加了一个引用System.Windows.Forms，但代码完成仍然没有显示InvokeRequired。列表视图位于与我调用它的线程不同的线程上，我需要使用 Invoke 解决该问题。你能告诉我我错过了什么吗？谢谢你。
Delegate Sub _AddClient(ByVal client As Socket)
Private Sub AddClient(ByVal client As Socket)
If InvokeRequired Then
Invoke(New _AddClient(AddressOf AddClient), client)
Exit Sub
End If
Dim lvi As New ListViewItem(client.LocalEndPoint.ToString)
lvi.Tag = client
lsvClients.Items.Add(lvi)
End Sub
回答by Federico Berasategui
Dude, if you're working with WPF, remove all references to System.Windows.Forms, WPF doesn't need, nor care about that, and you'd better not be confused with classes with equal names from different namespaces and frameworks (for instance System.Windows.Forms.Controland System.Windows.Control.
伙计，如果您正在使用 WPF，请删除对 的所有引用System.Windows.Forms，WPF 不需要，也不关心它，并且您最好不要与来自不同命名空间和框架的具有相同名称的类（例如System.Windows.Forms.Control和System.Windows.Control.
InvokeRequired()does not exist in WPF, that's replaced by Dispatcher.CheckAccess().
InvokeRequired()WPF 中不存在，而是由Dispatcher.CheckAccess().
回答by Hanlet Esca?o
Try this:
尝试这个：
Delegate Sub _AddClient(ByVal client As Socket)
Private Sub AddClient(ByVal client As Socket)
If ListView1.InvokeRequired Then
Invoke(New _AddClient(AddressOf AddClient), client)
Exit Sub
End If
Dim lvi As New ListViewItem(client.LocalEndPoint.ToString)
lvi.Tag = client
ListView1.Items.Add(lvi)
End Sub
回答by Pieter Geerkens
Here is an example of how it is used:
下面是一个如何使用它的例子：
protected void InvokePathDone(Task<IPath<ICoordsCanon>> task,
Action<Task<IPath<ICoordsCanon>>> action) {
if (InvokeRequired) Invoke(action, task);
else action(task);
}
Update for OP question below:
更新以下 OP 问题：
InvokeRequired()is defined for the Control class to enable callbacks from event delegates to determine if they are, or are not, on the UI thread, and thus whether they must, or must not, perform their action under Invoke().
InvokeRequired()为 Control 类定义以启用来自事件委托的回调，以确定它们是否在 UI 线程上，从而确定它们是否必须或不得在 Invoke() 下执行其操作。
