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<TypeSignature Language="C#" Value="public struct Message : IEquatable<System.Windows.Forms.Message>" FrameworkAlternate="windowsdesktop-10.0;windowsdesktop-11.0;windowsdesktop-7.0;windowsdesktop-8.0;windowsdesktop-9.0" />

<TypeSignature Language="ILAsm" Value=".class public sequential ansi sealed beforefieldinit Message extends System.ValueType implements class System.IEquatable`1<valuetype System.Windows.Forms.Message>" FrameworkAlternate="windowsdesktop-10.0;windowsdesktop-11.0;windowsdesktop-7.0;windowsdesktop-8.0;windowsdesktop-9.0" />

<TypeSignature Language="C++ CLI" Value="public value class Message : IEquatable<System::Windows::Forms::Message>" FrameworkAlternate="windowsdesktop-10.0;windowsdesktop-11.0;windowsdesktop-7.0;windowsdesktop-8.0;windowsdesktop-9.0" />

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

</TypeForwardingChain>

<Base>

<BaseTypeName>System.ValueType</BaseTypeName>

</Base>

<InterfaceName>System.IEquatable<System.Windows.Forms.Message></InterfaceName>

</Interface>

</Interfaces>

<Docs>

<summary>Implements a Windows message.</summary>

<format type="text/markdown"><![CDATA[

## Remarks

The <xref:System.Windows.Forms.Message> structure wraps messages that Windows sends. You can use this structure to wrap a message and assign it to the window procedure to be dispatched. You can also use this structure to get information about a message the system sends to your application or controls. For more information about Windows messages, see [Messages and Message Queues](https://go.microsoft.com/fwlink/?LinkId=198815).

You cannot create the <xref:System.Windows.Forms.Message> directly. Instead, use the <xref:System.Windows.Forms.Message.Create%2A> method. For the sake of efficiency, the <xref:System.Windows.Forms.Message> uses its pool of existing <xref:System.Windows.Forms.Message>s instead of instantiating a new one, if possible. However, if a <xref:System.Windows.Forms.Message> is not available in the pool, a new one is instantiated.

## Examples

The following code example demonstrates overriding the <xref:System.Windows.Forms.Control.WndProc%2A> method to handle operating system messages identified in the <xref:System.Windows.Forms.Message>. The WM_ACTIVATEAPP operating system message is handled in this example to know when another application is becoming active. For information about the available <xref:System.Windows.Forms.Message.Msg%2A?displayProperty=nameWithType>, <xref:System.Windows.Forms.Message.LParam%2A?displayProperty=nameWithType>, and <xref:System.Windows.Forms.Message.WParam%2A?displayProperty=nameWithType> values, see the [MSG Structure](https://go.microsoft.com/fwlink/?LinkId=198816) documentation. For information about the actual constant values, see [Message Constants](https://go.microsoft.com/fwlink/?LinkId=198817).

:::code language="cpp" source="~/snippets/cpp/VS_Snippets_Winforms/System.Windows.Forms.Control.WndProc/CPP/form1.cpp" id="Snippet1":::

:::code language="csharp" source="~/snippets/csharp/System.Windows.Forms/CheckedListBox/WndProc/form1.cs" id="Snippet1":::

:::code language="vb" source="~/snippets/visualbasic/System.Windows.Forms/CheckedListBox/WndProc/form1.vb" id="Snippet1":::

]]></format>

</remarks>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198815">Messages and Message Queues</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198816">MSG Structure</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198817">Message Constants</related>

</Docs>

<MemberSignature Language="F#" Value="static member Create : nativeint * int * nativeint * nativeint -> System.Windows.Forms.Message" Usage="System.Windows.Forms.Message.Create (hWnd, msg, wparam, lparam)" />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<ReturnType>System.Windows.Forms.Message</ReturnType>

</ReturnValue>

</Parameters>

<Docs>

<param name="hWnd">The window handle that the message is for.</param>

<param name="msg">The message ID.</param>

<param name="wparam">The message <paramref name="wparam" /> field.</param>

<param name="lparam">The message <paramref name="lparam" /> field.</param>

<summary>Creates a new <see cref="T:System.Windows.Forms.Message" />.</summary>

<returns>A <see cref="T:System.Windows.Forms.Message" /> that represents the message that was created.</returns>

<format type="text/markdown"><![CDATA[

## Remarks

Use the <xref:System.Windows.Forms.Message.Create%2A> method to create a <xref:System.Windows.Forms.Message> to wrap a message sent by Windows.

]]></format>

</remarks>

</Docs>

</Member>

<MemberSignature Language="F#" Value="override this.Equals : obj -> bool" Usage="message.Equals o" />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.Boolean</ReturnType>

</ReturnValue>

</Parameters>

<Docs>

<param name="o">The object to compare with the current object.</param>

<summary>Determines whether the specified object is equal to the current object.</summary>

<see langword="true" /> if the specified object is equal to the current object; otherwise, <see langword="false" />.</returns>

<remarks>To be added.</remarks>

</Docs>

</Member>

<MemberSignature Language="F#" Value="override this.Equals : System.Windows.Forms.Message -> bool" Usage="message.Equals other" />

<MemberType>Method</MemberType>

<InterfaceMember>M:System.IEquatable`1.Equals(`0)</InterfaceMember>

</Implements>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.Boolean</ReturnType>

</ReturnValue>

</Parameters>

<Docs>

<param name="other">An object to compare with this object.</param>

<summary>Indicates whether the current object is equal to another object of the same type.</summary>

<see langword="true" /> if the current object is equal to the <paramref name="other" /> parameter; otherwise, <see langword="false" />.</returns>

<remarks>To be added.</remarks>

</Docs>

</Member>

<MemberSignature Language="F#" Value="override this.GetHashCode : unit -> int" Usage="message.GetHashCode " />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.Int32</ReturnType>

</ReturnValue>

<Docs>

<summary>Returns the hash code for this instance.</summary>

<returns>A 32-bit signed integer that is the hash code for this instance.</returns>

<remarks>To be added.</remarks>

</Docs>

</Member>

<MemberSignature Language="F#" Value="member this.GetLParam : Type -> obj" Usage="message.GetLParam cls" />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.Object</ReturnType>

</ReturnValue>

<AttributeName Language="C#">[System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.NonPublicConstructors | System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]</AttributeName>

</Attribute>

</Attributes>

</Parameter>

</Parameters>

<Docs>

<param name="cls">The type to use to create an instance. This type must be declared as a structure type.</param>

<summary>Gets the <see cref="P:System.Windows.Forms.Message.LParam" /> value and converts the value to an object.</summary>

<returns>An <see cref="T:System.Object" /> that represents an instance of the class specified by the <paramref name="cls" /> parameter, with the data from the <see cref="P:System.Windows.Forms.Message.LParam" /> field of the message.</returns>

<format type="text/markdown"><![CDATA[

## Remarks

Use the <xref:System.Windows.Forms.Message.GetLParam%2A> method to retrieve information from the <xref:System.Windows.Forms.Message.LParam%2A> field of a message and convert it to an object. You can use this method to access objects passed in a message.

]]></format>

</remarks>

</Docs>

</Member>

<MemberType>Property</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[get: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[set: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[get: System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.IntPtr</ReturnType>

</ReturnValue>

<Docs>

<summary>Gets or sets the window handle of the message.</summary>

<value>The window handle of the message.</value>

<format type="text/markdown"><![CDATA[

## Remarks

*Window handle* is a value that uniquely identifies a window on the system. This property returns a handle of the window whose window procedure receives this message. It is useful when your code need to interact with some native Windows API functions that expect window handles as parameters.

]]></format>

</remarks>

<related type="ExternalDocumentation" href="/windows/desktop/winmsg/about-windows#window-handle">Window Handle</related>

</Docs>

</Member>

<MemberType>Property</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[get: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[set: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[get: System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.IntPtr</ReturnType>

</ReturnValue>

<Docs>

<summary>Specifies the <see cref="P:System.Windows.Forms.Message.LParam" /> field of the message.</summary>

<value>The <see cref="P:System.Windows.Forms.Message.LParam" /> field of the message.</value>

<format type="text/markdown"><![CDATA[

## Remarks

The value of this field depends on the message. Use the <xref:System.Windows.Forms.Message.LParam%2A> field to get information that is important for handling the message. <xref:System.Windows.Forms.Message.LParam%2A> is typically used to store an object if it is needed by the message. Use the <xref:System.Windows.Forms.Message.GetLParam%2A> method to retrieve and convert information from the <xref:System.Windows.Forms.Message.LParam%2A> field into an object.

]]></format>

</remarks>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198815">Messages and Message Queues</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198816">MSG Structure</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198817">Message Constants</related>

</Docs>

</Member>

<MemberType>Property</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[get: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[set: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[get: System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.Int32</ReturnType>

</ReturnValue>

<Docs>

<summary>Gets or sets the ID number for the message.</summary>

<value>The ID number for the message.</value>

<format type="text/markdown"><![CDATA[

## Examples

:::code language="cpp" source="~/snippets/cpp/VS_Snippets_Winforms/System.Windows.Forms.Control.WndProc/CPP/form1.cpp" id="Snippet1":::

:::code language="csharp" source="~/snippets/csharp/System.Windows.Forms/CheckedListBox/WndProc/form1.cs" id="Snippet1":::

:::code language="vb" source="~/snippets/visualbasic/System.Windows.Forms/CheckedListBox/WndProc/form1.vb" id="Snippet1":::

]]></format>

</remarks>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198815">Messages and Message Queues</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198816">MSG Structure</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198817">Message Constants</related>

</Docs>

</Member>

<MemberSignature Language="F#" Value="static member ( = ) : System.Windows.Forms.Message * System.Windows.Forms.Message -> bool" Usage="a = b" />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<ReturnType>System.Boolean</ReturnType>

</ReturnValue>

</Parameters>

<Docs>

<param name="a">A <see cref="T:System.Windows.Forms.Message" /> to compare to <paramref name="b" />.</param>

<param name="b">A <see cref="T:System.Windows.Forms.Message" /> to compare to <paramref name="a" />.</param>

<summary>Determines whether two instances of <see cref="T:System.Windows.Forms.Message" /> are equal.</summary>

<see langword="true" /> if <paramref name="a" /> and <paramref name="b" /> represent the same <see cref="T:System.Windows.Forms.Message" />; otherwise, <see langword="false" />.</returns>

</remarks>

</Docs>

</Member>

<MemberSignature Language="F#" Value="static member op_Inequality : System.Windows.Forms.Message * System.Windows.Forms.Message -> bool" Usage="System.Windows.Forms.Message.op_Inequality (a, b)" />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<ReturnType>System.Boolean</ReturnType>

</ReturnValue>

</Parameters>

<Docs>

<param name="a">A <see cref="T:System.Windows.Forms.Message" /> to compare to <paramref name="b" />.</param>

<param name="b">A <see cref="T:System.Windows.Forms.Message" /> to compare to <paramref name="a" />.</param>

<summary>Determines whether two instances of <see cref="T:System.Windows.Forms.Message" /> are not equal.</summary>

<see langword="true" /> if <paramref name="a" /> and <paramref name="b" /> do not represent the same <see cref="T:System.Windows.Forms.Message" />; otherwise, <see langword="false" />.</returns>

</remarks>

</Docs>

</Member>

<MemberType>Property</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[get: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[set: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[get: System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.IntPtr</ReturnType>

</ReturnValue>

<Docs>

<summary>Specifies the value that is returned to Windows in response to handling the message.</summary>

<value>The return value of the message.</value>

<remarks>To be added.</remarks>

</Docs>

</Member>

<MemberSignature Language="F#" Value="override this.ToString : unit -> string" Usage="message.ToString " />

<MemberType>Method</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.String</ReturnType>

</ReturnValue>

<Docs>

<summary>Returns a <see cref="T:System.String" /> that represents the current <see cref="T:System.Windows.Forms.Message" />.</summary>

<returns>A <see cref="T:System.String" /> that represents the current <see cref="T:System.Windows.Forms.Message" />.</returns>

<remarks>To be added.</remarks>

</Docs>

</Member>

<MemberType>Property</MemberType>

<AssemblyName>System.Windows.Forms</AssemblyName>

</AssemblyInfo>

<AssemblyName>System.Windows.Forms.Primitives</AssemblyName>

</AssemblyInfo>

<AttributeName Language="C#">[get: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[set: System.Runtime.TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]</AttributeName>

</Attribute>

<AttributeName Language="C#">[get: System.Runtime.CompilerServices.IsReadOnly]</AttributeName>

</Attribute>

</Attributes>

<ReturnType>System.IntPtr</ReturnType>

</ReturnValue>

<Docs>

<summary>Gets or sets the <see cref="P:System.Windows.Forms.Message.WParam" /> field of the message.</summary>

<value>The <see cref="P:System.Windows.Forms.Message.WParam" /> field of the message.</value>

<format type="text/markdown"><![CDATA[

## Remarks

The value of this field depends on the message. Use the <xref:System.Windows.Forms.Message.WParam%2A> field to get information that is important to handling the message. This field is typically used to store small pieces of information, such as flags.

## Examples

:::code language="cpp" source="~/snippets/cpp/VS_Snippets_Winforms/System.Windows.Forms.Control.WndProc/CPP/form1.cpp" id="Snippet1":::

:::code language="csharp" source="~/snippets/csharp/System.Windows.Forms/CheckedListBox/WndProc/form1.cs" id="Snippet1":::

:::code language="vb" source="~/snippets/visualbasic/System.Windows.Forms/CheckedListBox/WndProc/form1.vb" id="Snippet1":::

]]></format>

</remarks>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198815">Messages and Message Queues</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198816">MSG Structure</related>

<related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkId=198817">Message Constants</related>

</Docs>

</Member>

</Members>

</Type>

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