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Vb.net 创建一个文本框；提示“；两个不同文本框的消息（水印）

vb.net winforms

Vb.net 创建一个文本框；提示“；两个不同文本框的消息（水印）,vb.net,winforms,Vb.net,Winforms,我想知道如何为表单中的两个不同文本框创建“提示” 以下是我的代码： 导入系统运行时互操作服务 表单加载事件： SendMessage(Me.txtAmount.Handle, &H1501, 0, "$X.XX") SendMessage(Me.txtMemo.Handle, &H1501, 0, "Enter a transaction memo.") <DllImport("user32.dll", CharSet:=CharSet.Auto)> _ P

我想知道如何为表单中的两个不同文本框创建“提示”

以下是我的代码：

导入系统运行时互操作服务

表单加载事件：

SendMessage(Me.txtAmount.Handle, &H1501, 0, "$X.XX")
SendMessage(Me.txtMemo.Handle, &H1501, 0, "Enter a transaction memo.")

<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As Integer, <MarshalAs(UnmanagedType.LPWStr)> ByVal lParam As String) As Int32
    End Function
共享功能：

SendMessage(Me.txtAmount.Handle, &H1501, 0, "$X.XX")
SendMessage(Me.txtMemo.Handle, &H1501, 0, "Enter a transaction memo.")

<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As Integer, <MarshalAs(UnmanagedType.LPWStr)> ByVal lParam As String) As Int32
    End Function

_
私有共享函数SendMessage（ByVal hWnd作为IntPtr，ByVal msg作为Integer，ByVal wParam作为Integer，ByVal lParam作为String）作为Int32
端函数
此代码仅适用于
txtAmount
文本框。你知道如何让两个人以一种形式工作吗

谢谢。

创建一个类：

Public Class MultilineTextBoxWaterMark
Inherits TextBox

Private Const WM_PAINT = &HF

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
    MyBase.WndProc(m)

    If m.Msg = WM_PAINT Then
        If Text.Length <> 0 Or Me.Focused Then
            Return
        End If
        Using g As Graphics = Me.CreateGraphics, format As New StringFormat()
            format.LineAlignment = StringAlignment.Near

            g.DrawString("Enter a transaction memo.", Me.Font, Brushes.LightGray, Me.ClientRectangle, format)
        End Using
    End If
End Sub

End Class
我认为它有效。谢谢

创建一个类：

Public Class MultilineTextBoxWaterMark
Inherits TextBox

Private Const WM_PAINT = &HF

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
    MyBase.WndProc(m)

    If m.Msg = WM_PAINT Then
        If Text.Length <> 0 Or Me.Focused Then
            Return
        End If
        Using g As Graphics = Me.CreateGraphics, format As New StringFormat()
            format.LineAlignment = StringAlignment.Near

            g.DrawString("Enter a transaction memo.", Me.Font, Brushes.LightGray, Me.ClientRectangle, format)
        End Using
    End If
End Sub

End Class
我认为它有效。谢谢

您可以在不使用API的情况下复制文本框提示：

''' <summary>
''' Indicates the Textbox Hint.
''' </summary>
Private ReadOnly TextBoxHint As String = "I'm a control hint."

''' <summary>
''' Handles the Hint event of the TextBox control.
''' </summary>
''' <param name="sender">The source of the event.</param>
''' <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
Private Sub TextBox_Leave(ByVal sender As Object, ByVal e As EventArgs) Handles _
TextBox1.Leave, TextBox1.HandleCreated

    Select Case CStr(sender.Text)

        Case Is = TextBoxHint
            sender.text = String.Empty

        Case Is = String.Empty
            sender.text = TextBoxHint

    End Select

End Sub

''' <summary>
''' Handles the Enter event of the TextBox control.
''' </summary>
''' <param name="sender">The source of the event.</param>
''' <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
Private Sub TextBox_Enter(ByVal sender As Object, ByVal e As EventArgs) Handles _
TextBox1.Enter

    Select Case CStr(sender.Text)

        Case Is = TextBoxHint
            sender.text = String.Empty

    End Select

End Sub

“”
''表示文本框提示。
''' 
Private ReadOnly TextBoxHint As String=“我是一个控件提示。”
''' 
''处理TextBox控件的提示事件。
''' 
''事件的源头。
''包含事件数据的实例。
私有子文本框_Leave（ByVal sender作为对象，ByVal e作为事件args）句柄_
TextBox1.离开，TextBox1.HandleCreated
选择案例CStr（sender.Text）
Case Is=TextBoxHint
sender.text=String.Empty
Case Is=String.Empty
sender.text=TextBoxHint
结束选择
端接头
''' 
''处理TextBox控件的Enter事件。
''' 
''事件的源头。
''包含事件数据的实例。
私有子文本框（ByVal sender作为对象，ByVal e作为EventArgs）句柄_
TextBox1.输入
选择案例CStr（sender.Text）
Case Is=TextBoxHint
sender.text=String.Empty
结束选择
端接头
无论如何，试试这个替代方案，我同时在各种文本框上进行了测试，效果很好：

' Set Control Hint
' ( By Elektro )
'
' Usage Examples:
' SetControlHint(TextBox1, "I'm a text hint.")

''' <summary>
''' Messages to send to an Edit control, such a TextBox.
''' </summary>
Private Enum EditControlMessages As Integer

    ''' <summary>
    ''' Sets the textual cue, or tip, that is displayed by the edit control to prompt the user for information.
    ''' http://msdn.microsoft.com/en-us/library/windows/desktop/bb761639%28v=vs.85%29.aspx
    ''' </summary>
    SetCueBanner = &H1501I

End Enum

''' <summary>
''' Sends the specified message to a window or windows. 
''' The SendMessage function calls the window procedure for the specified window 
''' and does not return until the window procedure has processed the message.
''' http://msdn.microsoft.com/en-us/library/windows/desktop/ms644950%28v=vs.85%29.aspx
''' </summary>
''' <param name="hWnd">
''' A handle to the Control whose will receive the message.
''' </param>
''' <param name="msg">
''' The message to be sent.
''' </param>
''' <param name="wParam">
''' Additional message-specific information.
''' </param>
''' <param name="lParam">
''' Additional message-specific information.
''' </param>
''' <returns>
''' The return value specifies the result of the message processing; it depends on the message sent.
''' </returns>
<System.Runtime.InteropServices.DllImport("user32.dll",
EntryPoint:="SendMessage",
CharSet:=System.Runtime.InteropServices.CharSet.Auto)>
Private Shared Function SendEditMessage(
        ByVal hWnd As IntPtr,
        ByVal msg As EditControlMessages,
        ByVal wParam As IntPtr,
        <System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.LPWStr)>
        ByVal lParam As String
) As UInteger
End Function

''' <summary>
''' Sets a text hint for an edit control such a TextBox.
''' </summary>
''' <param name="Control">Indicates the control.</param>
''' <param name="Hint">Indicates the text hint.</param>
''' <returns><c>true</c> if operation succeeds, <c>false</c> otherwise.</returns>
Private Function SetControlHint(ByVal [Control] As Control,
                                ByVal Hint As String) As Boolean

    Return SendEditMessage([Control].Handle, EditControlMessages.SetCueBanner, IntPtr.Zero, Hint)

End Function

”设置控制提示
"(Elektro)
'
'用法示例：
'SetControlHint（TextBox1，“我是一个文本提示”）
''' 
''消息发送到编辑控件，如文本框。
''' 
私有枚举EditControlMessages作为整数
''' 
''设置编辑控件显示的文本提示或提示，以提示用户输入信息。
''' http://msdn.microsoft.com/en-us/library/windows/desktop/bb761639%28v=vs.85%29.aspx
''' 
SetCueBanner=&H1501I
结束枚举
''' 
''将指定的消息发送到一个或多个窗口。
''SendMessage函数调用指定窗口的窗口过程
''，直到窗口过程处理完消息后才返回。
''' http://msdn.microsoft.com/en-us/library/windows/desktop/ms644950%28v=vs.85%29.aspx
''' 
''' 
''将接收消息的控件的句柄。
''' 
''' 
''要发送的消息。
''' 
''' 
''其他消息特定信息。
''' 
''' 
''其他消息特定信息。
''' 
''' 
''返回值指定消息处理的结果；这取决于发送的消息。
''' 
私有共享函数SendEditMessage(
ByVal hWnd作为IntPtr，
ByVal msg作为EditControlMessages，
ByVal wParam作为IntPtr，
作为字符串的ByVal lParam
)作为尤因泰格
端函数
''' 
''为编辑控件（如文本框）设置文本提示。
''' 
''表示控件。
''表示文本提示。
''如果操作成功，则为true，否则为false。
私有函数SetControlHint（ByVal[Control]作为控件，
ByVal提示（作为字符串）作为布尔值
返回SendEditMessage（[Control].Handle，EditControlMessages.SetCueBanner，IntPtr.Zero，Hint）
端函数
您可以在不使用API的情况下复制文本框提示：

''' <summary>
''' Indicates the Textbox Hint.
''' </summary>
Private ReadOnly TextBoxHint As String = "I'm a control hint."

''' <summary>
''' Handles the Hint event of the TextBox control.
''' </summary>
''' <param name="sender">The source of the event.</param>
''' <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
Private Sub TextBox_Leave(ByVal sender As Object, ByVal e As EventArgs) Handles _
TextBox1.Leave, TextBox1.HandleCreated

    Select Case CStr(sender.Text)

        Case Is = TextBoxHint
            sender.text = String.Empty

        Case Is = String.Empty
            sender.text = TextBoxHint

    End Select

End Sub

''' <summary>
''' Handles the Enter event of the TextBox control.
''' </summary>
''' <param name="sender">The source of the event.</param>
''' <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
Private Sub TextBox_Enter(ByVal sender As Object, ByVal e As EventArgs) Handles _
TextBox1.Enter

    Select Case CStr(sender.Text)

        Case Is = TextBoxHint
            sender.text = String.Empty

    End Select

End Sub

“”
''表示文本框提示。
''' 
Private ReadOnly TextBoxHint As String=“我是一个控件提示。”
''' 
''处理TextBox控件的提示事件。
''' 
''事件的源头。
''包含事件数据的实例。
私有子文本框_Leave（ByVal sender作为对象，ByVal e作为事件args）句柄_
TextBox1.离开，TextBox1.HandleCreated
选择案例CStr（sender.Text）
Case Is=TextBoxHint
sender.text=String.Empty
Case Is=String.Empty
sender.text=TextBoxHint
结束选择
端接头
''' 
''处理TextBox控件的Enter事件。
''' 
''事件的源头。
''包含事件数据的实例。
私有子文本框（ByVal sender作为对象，ByVal e作为EventArgs）句柄_
TextBox1.输入
选择案例CStr（sender.Text）
Case Is=TextBoxHint
sender.text=String.Empty
结束选择
端接头
无论如何，试试这个替代方案，我同时在各种文本框上进行了测试，效果很好：

' Set Control Hint
' ( By Elektro )
'
' Usage Examples:
' SetControlHint(TextBox1, "I'm a text hint.")

''' <summary>
''' Messages to send to an Edit control, such a TextBox.
''' </summary>
Private Enum EditControlMessages As Integer

    ''' <summary>
    ''' Sets the textual cue, or tip, that is displayed by the edit control to prompt the user for information.
    ''' http://msdn.microsoft.com/en-us/library/windows/desktop/bb761639%28v=vs.85%29.aspx
    ''' </summary>
    SetCueBanner = &H1501I

End Enum

''' <summary>
''' Sends the specified message to a window or windows. 
''' The SendMessage function calls the window procedure for the specified window 
''' and does not return until the window procedure has processed the message.
''' http://msdn.microsoft.com/en-us/library/windows/desktop/ms644950%28v=vs.85%29.aspx
''' </summary>
''' <param name="hWnd">
''' A handle to the Control whose will receive the message.
''' </param>
''' <param name="msg">
''' The message to be sent.
''' </param>
''' <param name="wParam">
''' Additional message-specific information.
''' </param>
''' <param name="lParam">
''' Additional message-specific information.
''' </param>
''' <returns>
''' The return value specifies the result of the message processing; it depends on the message sent.
''' </returns>
<System.Runtime.InteropServices.DllImport("user32.dll",
EntryPoint:="SendMessage",
CharSet:=System.Runtime.InteropServices.CharSet.Auto)>
Private Shared Function SendEditMessage(
        ByVal hWnd As IntPtr,
        ByVal msg As EditControlMessages,
        ByVal wParam As IntPtr,
        <System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.LPWStr)>
        ByVal lParam As String
) As UInteger
End Function

''' <summary>
''' Sets a text hint for an edit control such a TextBox.
''' </summary>
''' <param name="Control">Indicates the control.</param>
''' <param name="Hint">Indicates the text hint.</param>
''' <returns><c>true</c> if operation succeeds, <c>false</c> otherwise.</returns>
Private Function SetControlHint(ByVal [Control] As Control,
                                ByVal Hint As String) As Boolean

    Return SendEditMessage([Control].Handle, EditControlMessages.SetCueBanner, IntPtr.Zero, Hint)

End Function

”设置控制提示
"(Elektro)
'
'用法示例：
'SetControlHint（TextBox1，“我是一个文本提示”）
''' 
''消息发送到编辑控件，如文本框。
''' 
私有枚举EditControlMessages作为整数
''' 
''设置编辑控件显示的文本提示或提示，以提示用户输入信息。
''' http://msdn.microsoft.com/en-us/library/windows/desktop/bb761639%28v=vs.85%29.aspx
''' 
SetCueBanner=&H1501I
结束枚举
''' 
''将指定的消息发送到一个或多个窗口。
''SendMessage函数调用指定窗口的窗口过程
''，直到窗口过程处理完消息后才返回。
''' http://msdn.microsoft.com/en-us/library/windows/desktop/ms644950%28v=vs.85%29.aspx
''' 
''' 
''将接收消息的控件的句柄。
''' 
''' 
''要发送的消息。
''' 
''' 
''其他消息特定信息。
''' 
''' 
''其他消息特定信息。
''' 
''' 
''返回值指定消息处理的结果；这取决于发送的消息。
''' 
私有共享函数SendEditMessage(
ByVal hWnd作为IntPtr，
ByVal msg作为EditControlMessages，
ByVal wParam作为IntPtr，
作为字符串的ByVal lParam
)作为