使用VB.Net的GhostText

发布时间：2020-12-17 07:21:12 所属栏目：百科来源：网络整理

导读：大家好,我试图在Textboxes上使用Labels创建一个鬼文本.我正在使用VB.Net2005.我用这段代码完成了这个： Public Class frmDataEntry Private Sub PhantomTextLastName() If txtLastName.Text = "" Then lblLastName.Visible = True Else lblLastName.Visible

大家好,我试图在Textboxes上使用Labels创建一个鬼文本.我正在使用VB.Net2005.我用这段代码完成了这个：

Public Class frmDataEntry

    Private Sub PhantomTextLastName()
        If txtLastName.Text = "" Then
            lblLastName.Visible = True
        Else
            lblLastName.Visible = False
        End If
    End Sub

    Private Sub PhantomTextFirstName()
        If txtFirstName.Text = "" Then
            lblFirstName.Visible = True
        Else
            lblFirstName.Visible = False
        End If
    End Sub

    Private Sub PhantomTextMiddleInitial()
        If txtMiddleInitial.Text = "" Then
            lblMiddleInitial.Visible = True
        Else
            lblMiddleInitial.Visible = False
        End If
    End Sub

    Private Sub txtLastName_Click(ByVal sender As Object,ByVal e As System.EventArgs) Handles txtLastName.Click
        lblLastName.Text = "Last Name"
    End Sub

    Private Sub txtLastName_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtLastName.KeyDown
        PhantomTextLastName()
    End Sub

    Private Sub txtLastName_TextChanged(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles txtLastName.TextChanged
        PhantomTextLastName()
    End Sub

    Private Sub lblLastName_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles lblLastName.Click
        txtLastName.Focus()
    End Sub

    Private Sub txtFirstName_Click(ByVal sender As Object,ByVal e As System.EventArgs) Handles txtFirstName.Click
        lblFirstName.Text = "First Name"
    End Sub

    Private Sub txtFirstName_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtFirstName.KeyDown
        PhantomTextFirstName()
    End Sub

    Private Sub txtFirstName_TextChanged(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles txtFirstName.TextChanged
        PhantomTextFirstName()
    End Sub

    Private Sub lblFirstName_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles lblFirstName.Click
        txtFirstName.Focus()
    End Sub

    Private Sub lblMiddleInitial_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles lblMiddleInitial.Click
        txtMiddleInitial.Focus()
    End Sub

    Private Sub txtMiddleInitial_Click(ByVal sender As Object,ByVal e As System.EventArgs) Handles txtMiddleInitial.Click
        lblMiddleInitial.Text = "Middle I."
    End Sub

    Private Sub txtMiddleInitial_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtMiddleInitial.KeyDown
        PhantomTextMiddleInitial()
    End Sub

    Private Sub txtMiddleInitial_TextChanged(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles txtMiddleInitial.TextChanged
        PhantomTextMiddleInitial()
    End Sub
End Class

有没有办法减少这个代码,所以当我尝试添加另一个文本框时,我将永远不必重新键入一堆代码.我有使用Module和Class的基本知识,但我真的不知道如何在这个项目中应用它.我是新手,如果你有任何教程可以帮助我解决这个问题,请给我链接.在此先感谢&上帝保佑.

解决方法

创建一个 usercontrol.您的usercontrol背后的代码可能是这样的：

Public Class GhostTextbox

    Private _ghostText As String
    Public Property GhostText As String
        Get
            Return _ghostText
        End Get
        Set(ByVal Value As String)
            _ghostText = Value
        End Set
    End Property

    Public Property ActualText As String
        Get
            Return Me.TextBox1.Text
        End Get
        Set(ByVal Value As String)
            Me.TextBox1.Text = Value
        End Set
    End Property

    Private Sub PhantomText()
        If TextBox1.Text = "" Then
            Label1.Visible = True
        Else
            Label1.Visible = False
        End If
    End Sub

    Private Sub TextBox1_Click(sender As Object,e As System.EventArgs) Handles TextBox1.Click
        Label1.Text = GhostText
    End Sub

    Private Sub TextBox1_KeyDown(sender As Object,e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
        PhantomText()
    End Sub

    Private Sub TextBox1_TextChanged(sender As System.Object,e As System.EventArgs) Handles TextBox1.TextChanged
        PhantomText()
    End Sub

    Private Sub GhostTextbox_Load(sender As Object,e As System.EventArgs) Handles Me.Load
        Label1.Text = GhostText
    End Sub
End Class

然后,使用此自定义控件而不仅仅是TextBox.您需要做的就是为您添加的每个新控件设置GhostText属性,而不是重新重新使用相同的逻辑.

（编辑：李大同）

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