C＃防止創建其他表格

Question

我有一個表格Form1，並帶有一個可創建其他表格的按鈕。但是，我只想一次創建1個附加表單。以下是我的代碼實現以下。我試圖使用Focus屬性，但它不起作用。

private void addLocation(object sender, MouseClickEventArgs e) 
{ 
    Form2 form2 = new Form2(); 
    form2.Show(); 
    form2.Focus(); 
} 

Answer 1

使用Application.OpenForms集合來檢查您是否已經打開了該窗體的實例。

private void addLocation(object sender, MouseClickEventArgs e) 
{ 
    Form2 form2 = Application.OpenForms.OfType<Form2>().SingleOrDefault(); 
    if(form2 == null) 
    { 
     form2 = new Form2(); 
     form2.Show(); 
     form2.Focus(); 
    } 
} 

Answer 2

您可以點擊按鈕改變光標然後還原代碼之後創建的形式完成或形式，它自

// Set cursor as hourglass 

Cursor.Current =光標禁用用戶.WaitCursor;

//這裏，可執行的時間密集型的散列碼...

//設置光標默認箭頭 Cursor.Current = Cursors.Default;

Answer 3

所以，如果形式打開了它應該被帶到前面和重點（顯示仿真），如果沒有則打開創建和顯示：

// If there're many instances, let's take the last one 
    Form2 form = Application.OpenForms 
    .OfType<Form2>() 
    .LastOrDefault(); 

    if (null == form) { 
    form = new From2(); 
    form.Show(); 
    } 
    else { 
    // Show emulation: 
    // - we don't want minimized window, 
    // - window should be at front 
    // - window should have a keyboard focus 

    if (form.WindowState == FormWindowState.Minimized) 
     form.WindowState = FormWindowState.Normal; 

    form.BringToFront(); 

    if (form.CanFocus) 
     form.Focus(); 
    }