控制Windows窗体的实例数 [英] Control Number of Instances of a Windows Form

问题描述

我有一个主 Windows表单，只有菜单条。所有其他表单都是
继承表单，可以使用菜单条中的工具条菜单项通过
点击事件处理程序。

I have a main Windows Form with just a Menu Strip. All other forms are inherited forms and can be accessed using the Tool Strip Menu Items in the Menu Strip via click event handlers.

private void toolStripMenuItemPersonnelInformation_Click(object sender, EventArgs e)
        {
            PersonnelInformation infoPersonnel = new PersonnelInformation();
            infoPersonnel.Show();
        }

如何防止启动同一表单的多个实例？我在上面的代码中添加了以下语句，以便禁用工具条菜单项。

How can I prevent multiple instances of the same form from being launched? I added the following statement to the above code in order to disable the Tool Strip Menu Item.

toolStripMenuItemPersonnelInformation.Enabled = false;

但是，它仅在主窗体中禁用，并且从未在继承的窗体中禁用。由于保护级别，我无法从继承的表单中禁用它。

However, it is only disabled in the main form and never disabled in the inherited form. I can't disable it from the inherited form due to the protection level.

谢谢，

Seif

推荐答案

创建一个类宽变量，表单显示并检查点击处理程序，如果有实际的实例，则返回此项，然后创建一个新实例：

create a class wide variable for the Form to show and check in the click handler if there's an actual instance then return this else create a new instance:

PersonnelInformation _infoPersonnel  = null;

private void toolStripMenuItemPersonnelInformation_Click(object sender, EventArgs e)
        {
            if(_infoPersonnel == null ||  _infoPersonnel.IsDisposed)
                _infoPersonnel = new PersonnelInformation();
            _infoPersonnel.Show();
        }

或在子表单中实现Singleton模式

or implement the Singleton pattern in the child-forms

问候，

  Thorsten

  Thorsten

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