vb.net 如何在 VB .NET 中设置 TextBox 提示标签？
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How to set TextBox hint label in VB .NET?
提问by Royal Pinto
In my application I have one text box for entering user name. If text is empty i want to show "Enter User name here" in same text box in gray color. Is there any property like this for text box. Like in Firefox browser if URL field is empty it will show "Go to a web site" In gray color
在我的应用程序中，我有一个用于输入用户名的文本框。如果文本为空，我想在同一文本框中以灰色显示“在此处输入用户名”。文本框是否有这样的属性。就像在 Firefox 浏览器中一样，如果 URL 字段为空，它将以灰色显示“转到网站”
Thanks
谢谢
回答by Grahamvs
I know this may be an old thread, but I thought I'd answer it just in case anyone else stumbled across it.
我知道这可能是一个旧线程，但我想我会回答它，以防其他人偶然发现它。
First declare the following (you may need to import System.Runtime.InteropServices)
首先声明以下内容（您可能需要导入System.Runtime.InteropServices）
<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
Then call the following (change as needed):
然后调用以下（根据需要更改）：
SendMessage(Me.textbox1.Handle, &H1501, 0, "Enter User name here")
回答by Dan Abramov
Assuming you mean Windows Forms, take a look at this question.
Basically, you need to call a WinAPI SendMessagefunction for the control with EM_SETCUEBANNERvalue.
假设您的意思是 Windows 窗体，请查看此问题。
基本上，您需要为SendMessage带有EM_SETCUEBANNER值的控件调用 WinAPI函数。
回答by nlinus
I really like this solution from CodeProject.com: http://www.codeproject.com/KB/edit/TextBoxHint.aspx?display=Print
我真的很喜欢 CodeProject.com 的这个解决方案：http: //www.codeproject.com/KB/edit/TextBoxHint.aspx?display= Print
What's really nice is the slick fade out as the user types in his/her text into the field. It's pretty darn easy to implement and looks great.
当用户在字段中输入他/她的文本时，光滑的淡出效果非常好。它非常容易实现并且看起来很棒。
回答by Ivan Ferrer Villa
you can subclass TextBox and override WndProc
您可以继承 TextBox 并覆盖 WndProc
Public Class TextBoxPlaceHolder
Inherits TextBox
Private Const WM_PAINT As Int32 = &HF
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
MyBase.WndProc(m)
If m.Msg = WM_PAINT AndAlso Me.TextLength = 0 Then
Using g = Me.CreateGraphics
g.DrawString("Enter User name here", Me.Font, Brushes.Gray, 1, 1)
End Using
End If
End Sub
End Class
回答by Isidoros Moulas
Awesome work Ivan and cardmagik. Create a usercontrol and use the below code.
很棒的工作 Ivan 和 cardmagik。创建一个用户控件并使用以下代码。
Public Class RichTextBoxPlaceHolder
Inherits RichTextBox
Private Const WM_PAINT As Int32 = &HF
Private mstrHint As String = "Enter text"
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
MyBase.WndProc(m)
If m.Msg = WM_PAINT AndAlso Me.TextLength = 0 Then
Using g = Me.CreateGraphics
g.DrawString(mstrHint, Me.Font, Brushes.Gray, 1, 1)
End Using
End If
End Sub
Public Property Hint() As String
Get
Return mstrHint
End Get
Set(ByVal value As String)
mstrHint = value
End Set
End Property
End Class
Screenshot:
截屏：
回答by Jared Ng
Try something along the lines of this:
尝试一些类似的东西：
(onkeyup)
If TextBox.Text = "" Then
TextBox.Text = "Enter username here..."
TextBox.ForeColor = <your chosen color here>
Else
TextBox.ForeColor = <normal color here>
End If
