vb.net查找以表格中指定字符串开头的控件

Question

I want to list all names of my buttons that begins with "btn" but these buttons are place in different panels. I have this in my mind

dim obj() as object in frmForm.Controls.Find(True,"btn*")

but I think it might be wrong..

Answer 1

First, the first parameter is the name and the second a bool which indicates whether you want to search recursively or not.

Second, there is no builtin way for this. I would use your own method, one like this:

Public Function FindControlStartsWith(root As Control, name As String, recursive As Boolean, comparison As StringComparison) As Control()
    If root Is Nothing Then
        Throw New ArgumentNullException("root")
    End If
    Dim controls = New List(Of Control)
    Dim stack = New Stack(Of Control)()
    stack.Push(root)

    While stack.Count > 0
        Dim c As Control = stack.Pop()
        If c.Name.StartsWith(name, comparison) Then
            controls.Add(c)
        End If
        If recursive Then
            For Each child As Control In root.Controls
                stack.Push(child)
            Next
        End If
    End While
    Return controls.ToArray()
End Function

Use it in this way:

Dim obj() As Control = FindControlStartsWith(Me, "BUT", True, StringComparison.OrdinalIgnoreCase)

Answer 2

I do something similar with the type of control, but it can easily be modified for name. Try the code below:

Private Sub findcontrols(ByVal root As Control)

    For Each cntrl As Control In root.Controls
        findcontrols(cntrl)
        If cntrl.name.startswith("btn") Then
            msgbox(cntrl.name)
        End If


End Sub

You can make this even more complex by adding parameters for stuff like controlling recursion and such. Keep in mind that if you want to do any control type-specific stuff with it (ie. anything that is in the control that is not inherited from the Control class), you need to CType that object as the appropriate control. So, if .name was only in the Button class, and did not exist in the Control class, I would have to do the following for this to work:

msgbox(ctype(cntrl, Button).name)

My own personal version of it looks more like this:

Private Sub clearcontrols(ByVal root As Control, ByVal ClearLists As Boolean, Optional ByVal ClearTabPages As Boolean = False)
    For Each cntrl As Control In root.Controls
        clearcontrols(cntrl, ClearLists, ClearTabPages)

        If TypeOf cntrl Is TextBox  Then
            CType(cntrl, TextBox).Clear()
        End If

        If TypeOf cntrl Is DataGridView Then
                CType(cntrl, DataGridView).Rows.Clear()
        End If

        If TypeOf cntrl Is ListBox   And ClearLists = True Then
                CType(cntrl, ListBox).Items.Clear()
        End If

        If TypeOf cntrl Is TabControl And ClearTabPages = True Then
            For Each tp As TabPage In CType(cntrl, TabControl).TabPages
                If DynTPList.Contains(tp.Name) Then
                    tp.Dispose()

                End If

            Next
        End If
    Next

End Sub