使用 vb.net 从其他形式获取标签的值
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Getting the value of the label from other form using vb.net
提问by Harvey
It is not working, the labels only goes back into its default values. What do you think is the problem?
它不起作用，标签只会恢复到其默认值。你认为有什么问题？
Okay this is my code:
好的，这是我的代码：
Actually I'm using mysql as my database here
实际上我在这里使用 mysql 作为我的数据库
This is the form that generates the values of the labels:
这是生成标签值的形式：
Private Sub ProfileControl_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Try
Dim conn As New MySqlConnection(ServerString)
Dim dap As New MySqlDataAdapter("select * from employee where LogInID = '" & Main.ID.Text & "'", conn)
Dim dt As New DataTable
dap.Fill(dt)
employeenum = dt.Rows(0).Item("EmployeeID")
position = dt.Rows(0).Item("Position")
employeename = dt.Rows(0).Item("FirstName") + " " + dt.Rows(0).Item("LastName")
lblemployeename.Text = employeename
lblemployeenum.Text = employeenum
EmpPosition.Text = position
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
And this is the form that will retrieve the values of the 3 labels.
这是将检索 3 个标签的值的表单。
Private Sub addsavebutton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles addsavebutton.Click
Dim profile As New ProfileControl
If txtbranchname.Text <> "" Then
If addsavebutton.Text = "ADD" Then
Dim zero As Integer = 0
Dim SQLStatement As String = "INSERT INTO branch(BranchName,Centers)VALUES('" & txtbranchname.Text & "','0') "
SaveCenter(SQLStatement)
logdate = Convert.ToDateTime(Date.Now).ToString("yyyy-MM-dd hh:mm:ss")
logdate2 = Format(Date.Now, "yyyy-MM-dd")
status = "Added Branch " + txtbranchname.Text
SQLStatement = "INSERT INTO log(EmployeeID,Name,EmployeePosition,Date,DateTime,Status)VALUES('" & profile.lblemployeenum.Text & "','" & profile.lblemployeename.Text & "','" & profile.EmpPosition.Text & "','" & logdate2 & "','" & logdate & "','" & status & "' )"
Savelog(SQLStatement)
txtbranchname.Clear()
ElseIf addsavebutton.Text = "SAVE" Then
Dim Query As String
Dim con As MySqlConnection = New MySqlConnection(ServerString)
con.Open()
Query = "UPDATE branch SET BranchName = '" & txtbranchname.Text & "' WHERE BranchCode = '" & txtbranchcode.Text & "'"
Dim cmd As MySqlCommand = New MySqlCommand(Query, con)
Dim i As Integer = cmd.ExecuteNonQuery()
If (i > 0) Then
'success
Dim Successtext As New MsgSuccess
Successtext.PassedText = "Record is Successfully Updated"
Successtext.ShowDialog()
Dim SQLStatement As String
logdate = Convert.ToDateTime(Date.Now).ToString("yyyy-MM-dd hh:mm:ss")
logdate2 = Format(Date.Now, "yyyy-MM-dd")
status = "Updated Branch: " + txtbranchcode.Text + ", " + txtbranchname.Text
SQLStatement = "INSERT INTO log(EmployeeID,Name,EmployeePosition,Date,DateTime,Status)VALUES('" & profile.lblemployeenum.Text & "','" & profile.lblemployeename.Text & "','" & Main.lbldate.Text & "','" & logdate2 & "','" & logdate & "','" & status & "' )"
Savelog(SQLStatement)
srchTextBox.Clear()
con.Close()
Else
'error
Dim Errortext As New Msgerror
Errortext.PassedText = "Record is not Updated"
Errortext.ShowDialog()
End If
End If
Else
Dim Errortext As New Msgerror
Errortext.PassedText = "All Entries with * must be filled"
Errortext.ShowDialog()
End If
End Sub
回答by Cubsoft
Firstly, create an instance of your form2 in form1.
首先，在form1 中创建一个form2 的实例。
Dim secondform As New Form2
On your form2, go to the 'modifiers' property of your three labels and change it to public.
在您的 form2 上，转到三个标签的 'modifiers' 属性并将其更改为 public。
Then you can set variables in form1 to get the value of the labels like the following;
然后你可以在form1中设置变量来获取标签的值，如下所示；
Dim a As String = secondform.lblemployeename.Text
Dim b As String = secondform.lblemployeenum.Text
Dim c As String = secondform.lblEmpPosition.Text
This should make 'a', 'b' and 'c' the value of your labels
这应该使 'a'、'b' 和 'c' 成为标签的值
回答by SysDragon
Looks like you are creating an instance of your form (Dim profile As New ProfileControl) and then you try to access his controls values. Dont you have a ProfileControlalready created?
看起来您正在创建表单 ( Dim profile As New ProfileControl) 的一个实例，然后您尝试访问他的控件值。你不是ProfileControl已经创建了吗？
Anyway, if ProfileControlis a form, the Loadevent will only execute when the form loads (when you show the form), so the values for the labels are not getting loaded.
无论如何，如果ProfileControl是表单，则Load事件只会在表单加载时（当您显示表单时）执行，因此标签的值不会被加载。
If you are showing the form already, dont create that instance and use the form name that you showed to access the labels.
如果您已经在显示表单，请不要创建该实例并使用您显示的表单名称来访问标签。
If you are not showing the form, you should consider creating that values in another variables and later assign it to the labels or create your own class, etc.
如果您不显示表单，则应考虑在另一个变量中创建该值，然后将其分配给标签或创建您自己的类等。
回答by SysDragon
Just add the controls from the form's name:
只需添加表单名称中的控件：
Form2.lblemployeename.Text
Form2.lblemployeenum.Text
Form2.lblEmpPosition.Text
For me, in VB.NET 2.0 with VS2005, the controls are created Friend. Check the form designer and put your controls on Publicor Friend(and With Eventsif you need it) in order to use them from other forms.
对我来说，在带有 VS2005 的 VB.NET 2.0 中，控件是创建的Friend。检查表单设计器并将您的控件放在Public或Friend（With Events如果您需要的话）上，以便从其他表单中使用它们。
