Form 类
表示组成应用程序的用户界面的窗口或对话框。
**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）
语法
声明
<ComVisibleAttribute(True)> _
<ClassInterfaceAttribute(ClassInterfaceType.AutoDispatch)> _
Public Class Form
Inherits ContainerControl
用法
Dim instance As Form
[ComVisibleAttribute(true)]
[ClassInterfaceAttribute(ClassInterfaceType.AutoDispatch)]
public class Form : ContainerControl
[ComVisibleAttribute(true)]
[ClassInterfaceAttribute(ClassInterfaceType::AutoDispatch)]
public ref class Form : public ContainerControl
/** @attribute ComVisibleAttribute(true) */
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.AutoDispatch) */
public class Form extends ContainerControl
ComVisibleAttribute(true)
ClassInterfaceAttribute(ClassInterfaceType.AutoDispatch)
public class Form extends ContainerControl
备注
Form 是应用程序中所显示的任何窗口的表示形式。Form 类可用于创建标准窗口、工具窗口、无边框窗口和浮动窗口。您还可以使用 Form 类创建模式窗口，例如对话框。一种特殊类型的窗体，即多文档界面 (MDI) 窗体可包含其他称为 MDI 子窗体的窗体。通过将 IsMdiContainer 属性设置为 true 来创建 MDI 窗体。通过将 MdiParent 属性设置为将包含 MDI 子窗体的 MDI 父窗体来创建 MDI 子窗体。
使用 Form 类中可用的属性，您可以确定所创建窗口或对话框的外观、大小、颜色和窗口管理功能。Text 属性允许您在标题栏中指定窗口的标题。Size 和 DesktopLocation 属性允许您定义窗口在显示时的大小和位置。您可以使用 ForeColor 颜色属性更改窗体上放置的所有控件的默认前景色。FormBorderStyle、MinimizeBox 和 MaximizeBox 属性允许您控制运行时窗体是否可以最小化、最大化或调整窗体大小。
除了属性之外，您还可以使用此类的方法来操作窗体。例如，您可以使用 ShowDialog 方法将窗体显示为模式对话框。可以使用 SetDesktopLocation 方法在桌面上定位窗体。
Form 类的事件允许您响应对窗体执行的操作。可以使用 Activated 事件执行操作，如当窗体已激活时更新窗体控件中显示的数据。
可以通过在类中放置称为 Main 的方法将窗体用作应用程序中的启动类。在 Main 方法中添加代码，以创建和显示窗体。为了运行窗体，您还需要在 Main 方法中添加 STAThread 属性。关闭启动窗体时，应用程序也同时关闭。
示例
下面的代码示例创建 Form 的一个新实例，并调用 ShowDialog 方法以将该窗体显示为对话框。该示例设置 FormBorderStyle、AcceptButton、CancelButton、MinimizeBox、MaximizeBox 和 StartPosition 属性，将窗体的外观和功能更改为对话框形式。该示例还使用窗体的 Controls 集合的 Add 方法来添加两个 Button 控件。该示例使用 HelpButton 属性来在对话框的标题栏中显示“帮助”按钮。
Public Sub CreateMyForm()
' Create a new instance of the form.
Dim form1 As New Form()
' Create two buttons to use as the accept and cancel buttons.
Dim button1 As New Button()
Dim button2 As New Button()
' Set the text of button1 to "OK".
button1.Text = "OK"
' Set the position of the button on the form.
button1.Location = New Point(10, 10)
' Set the text of button2 to "Cancel".
button2.Text = "Cancel"
' Set the position of the button based on the location of button1.
button2.Location = _
New Point(button1.Left, button1.Height + button1.Top + 10)
' Set the caption bar text of the form.
form1.Text = "My Dialog Box"
' Display a help button on the form.
form1.HelpButton = True
' Define the border style of the form to a dialog box.
form1.FormBorderStyle = FormBorderStyle.FixedDialog
' Set the MaximizeBox to false to remove the maximize box.
form1.MaximizeBox = False
' Set the MinimizeBox to false to remove the minimize box.
form1.MinimizeBox = False
' Set the accept button of the form to button1.
form1.AcceptButton = button1
' Set the cancel button of the form to button2.
form1.CancelButton = button2
' Set the start position of the form to the center of the screen.
form1.StartPosition = FormStartPosition.CenterScreen
' Add button1 to the form.
form1.Controls.Add(button1)
' Add button2 to the form.
form1.Controls.Add(button2)
' Display the form as a modal dialog box.
form1.ShowDialog()
End Sub
public void CreateMyForm()
{
// Create a new instance of the form.
Form form1 = new Form();
// Create two buttons to use as the accept and cancel buttons.
Button button1 = new Button ();
Button button2 = new Button ();
// Set the text of button1 to "OK".
button1.Text = "OK";
// Set the position of the button on the form.
button1.Location = new Point (10, 10);
// Set the text of button2 to "Cancel".
button2.Text = "Cancel";
// Set the position of the button based on the location of button1.
button2.Location
= new Point (button1.Left, button1.Height + button1.Top + 10);
// Set the caption bar text of the form.
form1.Text = "My Dialog Box";
// Display a help button on the form.
form1.HelpButton = true;
// Define the border style of the form to a dialog box.
form1.FormBorderStyle = FormBorderStyle.FixedDialog;
// Set the MaximizeBox to false to remove the maximize box.
form1.MaximizeBox = false;
// Set the MinimizeBox to false to remove the minimize box.
form1.MinimizeBox = false;
// Set the accept button of the form to button1.
form1.AcceptButton = button1;
// Set the cancel button of the form to button2.
form1.CancelButton = button2;
// Set the start position of the form to the center of the screen.
form1.StartPosition = FormStartPosition.CenterScreen;
// Add button1 to the form.
form1.Controls.Add(button1);
// Add button2 to the form.
form1.Controls.Add(button2);
// Display the form as a modal dialog box.
form1.ShowDialog();
}
public:
void CreateMyForm()
{
// Create a new instance of the form.
Form^ form1 = gcnew Form;
// Create two buttons to use as the accept and cancel buttons.
Button^ button1 = gcnew Button;
Button^ button2 = gcnew Button;
// Set the text of button1 to "OK".
button1->Text = "OK";
// Set the position of the button on the form.
button1->Location = Point(10,10);
// Set the text of button2 to "Cancel".
button2->Text = "Cancel";
// Set the position of the button based on the location of button1.
button2->Location =
Point( button1->Left, button1->Height + button1->Top + 10 );
// Set the caption bar text of the form.
form1->Text = "My Dialog Box";
// Display a help button on the form.
form1->HelpButton = true;
// Define the border style of the form to a dialog box.
form1->FormBorderStyle = ::FormBorderStyle::FixedDialog;
// Set the MaximizeBox to false to remove the maximize box.
form1->MaximizeBox = false;
// Set the MinimizeBox to false to remove the minimize box.
form1->MinimizeBox = false;
// Set the accept button of the form to button1.
form1->AcceptButton = button1;
// Set the cancel button of the form to button2.
form1->CancelButton = button2;
// Set the start position of the form to the center of the screen.
form1->StartPosition = FormStartPosition::CenterScreen;
// Add button1 to the form.
form1->Controls->Add( button1 );
// Add button2 to the form.
form1->Controls->Add( button2 );
// Display the form as a modal dialog box.
form1->ShowDialog();
}
public void CreateMyForm()
{
// Create a new instance of the form.
Form form1 = new Form();
// Create two buttons to use as the accept and cancel buttons.
Button button1 = new Button();
Button button2 = new Button();
// Set the text of button1 to "OK".
button1.set_Text("OK");
// Set the position of the button on the form.
button1.set_Location(new Point(10, 10));
// Set the text of button2 to "Cancel".
button2.set_Text("Cancel");
// Set the position of the button based on the location of button1.
button2.set_Location(new Point(button1.get_Left(),
button1.get_Height() + button1.get_Top() + 10));
// Set the caption bar text of the form.
form1.set_Text("My Dialog Box");
// Display a help button on the form.
form1.set_HelpButton(true);
// Define the border style of the form to a dialog box.
form1.set_FormBorderStyle(get_FormBorderStyle().FixedDialog);
// Set the MaximizeBox to false to remove the maximize box.
form1.set_MaximizeBox(false);
// Set the MinimizeBox to false to remove the minimize box.
form1.set_MinimizeBox(false);
// Set the accept button of the form to button1.
form1.set_AcceptButton(button1);
// Set the cancel button of the form to button2.
form1.set_CancelButton(button2);
// Set the start position of the form to the center of the screen.
form1.set_StartPosition(FormStartPosition.CenterScreen);
// Add button1 to the form.
form1.get_Controls().Add(button1);
// Add button2 to the form.
form1.get_Controls().Add(button2);
// Display the form as a modal dialog box.
form1.ShowDialog();
} //CreateMyForm
继承层次结构
System.Object
System.MarshalByRefObject
System.ComponentModel.Component
System.Windows.Forms.Control
System.Windows.Forms.ScrollableControl
System.Windows.Forms.ContainerControl
System.Windows.Forms.Form
派生类
线程安全
此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。
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、1.0