如何创建在按钮单击事件上实例化的winform的单个实例？ [英] How to create a single instance of a winform that is instantiated on a button click event?

问题描述

正在处理一个带有按钮的Windows应用程序表单（FormA），在button_click事件中我希望实例化另一个Windows窗体（FormB），这是来自主winform（FormA）的单独winform。我想要实例化新的实例化的winform（FormB）只有一个实例，在按钮点击事件时它不应该创建另一个winform（FormB）。除了使用FormB的单例模式之外，有没有办法做到这一点？期待逻辑方法作为答案......请给出一些选择..



我尝试过：



期待有效的方法..

m working on an windows application form(FormA) that has a button,upon button_click event i want another windows form(FormB) instantiated,which is a seperate winform from the main winform (FormA).i want to instantiate the newly instantiated winform(FormB) to have only a single instance,upon button click event it should not create another winform(FormB).is there a way to do this other than using singleton pattern for FormB??Expecting logical approach as answers...Pls give some options..

What I have tried:

expecting efficient approaches..

推荐答案

如果提到NotPoliticallyCorrect，如果表单已打开，则应禁用该按钮。



但是要回答你的问题，以下代码可以满足您的要求：

As NotPoliticallyCorrect mentioned, if the form is open, the button should be disabled.

But to answer your question, the following code does what you ask:

private void ButtonClick(object sender, EventArgs e)
{
    Form form = null;
    if (sender == button1)
    {
        if (Application.OpenForms[nameof(Form1)] == null)
            form = new Form1();
    }
    else // button2
    {
        if (Application.OpenForms[nameof(Form2)] == null)
            form = new Form2();
    }
    if (form != null)
    {
        form.Owner = this;
        form.Show();
    }
}

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