Form.Activate 方法

  • 项目

激活窗体并给予它焦点。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Sub Activate
用法
Dim instance As Form

instance.Activate

public void Activate ()

public:
void Activate ()

public void Activate ()

public function Activate ()

备注

如果这是活动应用程序，则激活窗体会将该窗体置于前面；或者如果这不是活动应用程序，则激活窗体会使窗口标题闪烁。该窗体必须对此方法可见，才能产生效果。若要确定应用程序中的活动窗体，请使用 ActiveForm 属性或 ActiveMdiChild 属性（如果窗体在多文档界面 (MDI) 应用程序中）。

示例

下面的代码示例阐释了如何使用 SetDesktopLocation、Load 和 Activate 成员。若要运行此示例，请将以下代码粘贴到一个名为 Form1 的窗体中，该窗体含有一个名为 Button1 的按钮和两个分别名为 Label1 和 Label2 的 Label 控件。

Shared x As Integer = 200
Shared y As Integer = 200

Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click

    ' Create a new Form1 and set its Visible property to true.
    Dim form2 As New Form1
    form2.Visible = True

    ' Set the new form's desktop location so it appears below and 
    ' to the right of the current form.
    form2.SetDesktopLocation(x, y)
    x += 30
    y += 30

    ' Keep the current form active by calling the Activate method.
    Me.Activate()
    Me.Button1.Enabled = False
End Sub



' Updates the label text to reflect the current values of x and y, 
' which was were incremented in the Button1 control's click event.
Private Sub Form1_Activated(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles MyBase.Activated
    Label1.Text = "x: " & x & " y: " & y
    Label2.Text = "Number of forms currently open: " & count
End Sub

Shared count As Integer = 0

Private Sub Form1_Closed(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles MyBase.Closed
    count -= 1
End Sub

Private Sub Form1_Load(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles MyBase.Load
    count += 1
End Sub

static int x = 200;
static int y = 200;

private void Button1_Click(System.Object sender, 
    System.EventArgs e)
{
    // Create a new Form1 and set its Visible property to true.
    Form1 form2 = new Form1();
    form2.Visible = true;

    // Set the new form's desktop location so it  
    // appears below and to the right of the current form.
    form2.SetDesktopLocation(x, y);
    x += 30;
    y += 30;

    // Keep the current form active by calling the Activate
    // method.
    this.Activate();
    this.Button1.Enabled = false;
}



// Updates the label text to reflect the current values of x 
// and y, which was were incremented in the Button1 control's 
// click event.
private void Form1_Activated(object sender, System.EventArgs e)
{
    Label1.Text = "x: "+x+" y: "+y;
    Label2.Text = "Number of forms currently open: "+count;
}

static int count = 0;

private void Form1_Closed(object sender, System.EventArgs e)
{
    count -= 1;
}

private void Form1_Load(object sender, System.EventArgs e)
{
    count += 1;
}

static int x = 200;
static int y = 200;
void Button1_Click( System::Object^ sender, System::EventArgs^ e )
{
   
   // Create a new Form1 and set its Visible property to true.
   Form1^ form2 = gcnew Form1;
   form2->Visible = true;
   
   // Set the new form's desktop location so it  
   // appears below and to the right of the current form.
   form2->SetDesktopLocation( x, y );
   x += 30;
   y += 30;
   
   // Keep the current form active by calling the Activate
   // method.
   this->Activate();
   this->Button1->Enabled = false;
}


// Updates the label text to reflect the current values of x 
// and y, which was were incremented in the Button1 control's 
// click event.
void Form1_Activated( Object^ sender, System::EventArgs^ e )
{
   Label1->Text = String::Format( "x: {0} y: {1}", x, y );
   Label2->Text = String::Format( "Number of forms currently open: {0}", count );
}

static int count = 0;
void Form1_Closed( Object^ sender, System::EventArgs^ e )
{
   count -= 1;
}

void Form1_Load( Object^ sender, System::EventArgs^ e )
{
   count += 1;
}

private static int x = 200;
private static int y = 200;

private void button1_Click(Object sender, System.EventArgs e)
{
    // Create a new Form1 and set its Visible property to true.
    Form1 form2 = new Form1();
    form2.set_Visible(true);
    // Set the new form's desktop location so it  
    // appears below and to the right of the current form.
    form2.SetDesktopLocation(x, y);
    x += 30;
    y += 30;
    // Keep the current form active by calling the Activate
    // method.
    this.Activate();
    this.button1.set_Enabled(false);
} //button1_Click

// Updates the label text to reflect the current values of x 
// and y, which was were incremented in the button1 control's 
// click event.
private void Form1_Activated(Object sender, System.EventArgs e)
{
    label1.set_Text("x: " + x + " y: " + y);
    label2.set_Text("Number of forms currently open: " + count);
} //Form1_Activated

private static int count = 0;

private void Form1_Closed(Object sender, System.EventArgs e)
{
    count -= 1;
} //Form1_Closed

private void Form1_Load(Object sender, System.EventArgs e)
{
    count += 1;
} //Form1_Load

.NET Framework 安全性

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

.NET Compact Framework

受以下版本支持：2.0

请参见

参考

Form 类
Form 成员
System.Windows.Forms 命名空间
ActiveForm
ActiveMdiChild