如何在VB中动态添加文本框、标签和按钮？

Question

如何在VB中创建一个带有按钮add_subjects的表单，每次点击该按钮会添加一个textbox和相应的标签，除此之外还需要为每个在运行时创建的textbox添加3个按钮 - 添加、编辑和删除。当点击每个textbox相应的Add_button时，它会将textbox的值传递给标签。

- user3172488

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为什么不使用数据网格并在其中编辑所有内容？ - DevelopmentIsMyPassion

Answer 1

Private Property number as Integer=1

Private Sub add_subject_Click(sender As Object, e As EventArgs) Handles add_subject.Click
    Dim tb As New TextBox
    tb.Name="TextBox"+number.ToString
    tb.Position = New Point(number*40,10) ' change this if you want
    Me.Controls.Add(tb)
    Dim lb As New Label
    lb.Name="Label"+number.ToString
    lb.Position = New Point(number*40,50) ' change this if you want
    Me.Controls.Add(lb)
    Dim add As New Button
    add.Name="AddButton"+number.ToString
    add.Position = New Point(number*40,100) ' change this if you want
    AddHandler(add.Click, AdressOf(add_Click))
    Me.Controls.Add(add)
    Dim edit As New Button
    edit.Name="EditButton"+number.ToString
    edit.Position = New Point(number*40,150) ' change this if you want
    AddHandler(edit.Click, AdressOf(edit_Click))'you have to make edit_Click
    YourForm.Controls.Add(edit)
    Dim delete As New Button
    delete.Name="DeleteButton"+number.ToString
    delete.Position = New Point(number*40,200) ' change this if you want
    AddHandler(delete.Click, AdressOf(delete_Click))'you have to make delete_Click
    Me.Controls.Add(delete)
    number+=1
End Sub

因此，我们动态生成所有控件的名称、更改位置、添加处理程序并将控件添加到表单中。

Private Sub add_Click(sender As Object, e As EventArgs)
    Ctype(Me.Controls.Find("Label"+sender.Name.Substring(9),True).First,Label).Text = Ctype(Me.Controls.Find("TextBox"+sender.Name.Substring(9),True).First,TextBox).Text 
End Sub

在这里，我们使用发送者的编号找到Label和TextBox(sender.Name.Substring(9)将删除AddButton并留下数字)，并将Label.Text更改为TextBox.Text。

获取所有标签值并将它们插入数据库：

Private Sub save(sender As Object, e as EventArgs) Handles button_save_subjects.Click
For i = 1 to number
    Dim value As String
    value = CType(Me.Controls.Find("Label"+number.ToString).First,Label).Text
    'insert into database
Next
End Sub

- srka

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是否可以跟踪每个动态创建的标签及其值，以便我可以使用嵌入在button_save_subjects事件中的SQL将这些标签的值存储为数据库表字段？ - user3172488

我添加了代码以获取所有值，但我不懂SQL，所以您需要将值插入数据库中。 - srka

Answer 2

像文本框这样的控件只是 Textbox 类的一个对象。为了让窗体显示该对象，需要将其添加到窗体的 Controls 属性中。要创建一个新的文本框只需执行以下操作：

Dim newTB as New Textbox
newTB.Name = "tbNew"
'Set location, size and so on if you like
Me.Controls.Add(newTB)

如果您希望控件能够响应事件，您需要为您想要的事件向该控件添加一个事件处理程序。此处理程序将该事件引用到您选择的方法。

Public Class Form1

  Sub CreateTB
    Dim NewTB as New Textbox
    newTB = New Textbox
    newTB.Name = "tbNew"
    AddHandler newTB.TextChanged, AddressOf HandleTextChanged
    Me.Controls.Add(newTB)
  End Sub


  Private Sub HandleTextChanged(sender as Object, e as EventArgs)
    'Handle the event
  End Sub
End Class

如果您正在创建控件，一定要确保名称是唯一的，否则可能会遇到麻烦。

您还可以将创建的控件存储在全局变量的数组或列表中。这样做可以方便地在之后进行访问。

- Jens

Answer 3

创建动态文本框。

Private Sub btnCreateTextbox_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCreateTextbox.Click
        Dim textbox1 As New TextBox
        textbox1.Name = "Textbox1"
        textbox1.Size = New Size(170, 20)
        textbox1.Location = New Point(167, 32)
        GroupBox1.Controls.Add(textbox1)
  End Sub

创建动态标签。

Private Sub lblCreateLabel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lblCreateLabel.Click
    Dim label1 As New Label
    label1.Name = "label1"
    label1.Text = "Enter Name"
    label1.AutoSize = True
    label1.Location = New Point(80, 33)
    GroupBox1.Controls.Add(label1)
End Sub

请参阅此处

来源

- Vignesh Kumar A

Answer 4

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Call AddTextBox()
End Sub

Sub AddTextBox()

    Dim i As Integer = 1

    For Each ctrl In Me.Controls
        If TypeOf ctrl Is TextBox Then
            i = i + 1
            'MsgBox(i)
        End If
    Next ctrl

    Dim Label As New Label
    Label.Name = "Label" & i
    Label.Size = New Size(170, 20)
    Label.Location = New Point(200, (20 + (i * 55)))
    Label.Text = "Lbl" & i

    Dim Textbox As New TextBox
    Textbox.Name = "Textbox" & i
    Textbox.Size = New Size(170, 20)
    Textbox.Location = New Point(200, (38 + (i * 55)))
    Me.Controls.Add(Label)
    Me.Controls.Add(Textbox)


End Sub

- Austin

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可以提供一些背景信息，让其他人了解你为什么建议这个解决方案吗？ - Seth

Answer 5

您可以使用与上面相同的代码，并最终使用控件的父属性。 因为控件（TextBox、Button等）位于“容器”（表单、GroupBox等）之内。就像这样...

  ...
  Dim textbox1 As New TextBox
  textbox1.Name = "Textbox1" 'or other
  ...
  textbox1.parent = Me 'Me = the form
  ...

- eduardo figueiredo