如何检查Windows Forms Instance是否运行? [英] How to check windows Forms Instance running or not ?

问题描述

亲爱的，

请，有人能告诉我如何检查Windows窗体实例当前正在运行吗?我有Button显示第二个窗体，但是需要知道它是否已打开?

Dears,

please, Can anyone tell me how to check Windows forms instance is running at presently?I have Button to display second form,But need to know its already opened or not ?

推荐答案

要阻止多个实例，您可以查看此 [此 [ VB.NET中的单实例应用程序中的另一个有用链接 [

To block mulitple instances, you can have a look at this[^]. The code is in C#, but you might be able to convert it to VB.Net.

If the form is a form (application) you coded, you can control the number of instances by using code similar to this[^].

Another useful link at Single Instance Application in VB.NET[^].

有两种方法:
您可以在当前的表单类中保留对它的引用，并检查:

There are a couple of ways:
You could keep a reference to it in your current form class, and check that:

private MyForm myForm = null;
private void OpenNewMyFormInstance()
    {
    if (myForm == null)
        {
        myForm = new MyForm();
        myForm.FormClosed += new FormClosedEventHandler(myForm_FormClosed);
        myForm.Show();
        }
    }
void myForm_FormClosed(object sender, FormClosedEventArgs e)
    {
    myForm = null;
    }

您需要处理FormClosed事件以注册用户已将其关闭.

或者，您可以检查现有实例:

You need to handle the FormClosed event to register that the user closed it.

Or, you could check for an existing instance:

bool isMyFormOpen = false;
foreach (Form f in Application.OpenForms)
    {
    if (f is MyForm)
        {
        isMyFormOpen = true;
        break;
        }
    }
if (!isMyFormOpen)
    {
    MyForm f = new MyForm();
    f.Show();
    }

我?我会保留该引用，因为我可能想将其用于其他用途.

Me? I''d keep the reference, because I might want to use it for something else.

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