How to retrieve clipboard format and data from any application

Question

How can I use Visual Basic (VB) to retrieve the format and data stored on the clipboard of any running application? I want to build a tool that extracts this information.

As you can see in the program, I copy and paste the rectangle. I want to retrieve the clipboard data so that I can get the size of the rectangle.

Answer 1

In your GIF, this app uses a custom Clipboard format (PXCEditCbData), so it cannot be generic

With this test, I get the size of the Rectangle from PXCEditCbData (nValues array), but it will be different for any other application :

Public Class Form1

    Private Const WM_CLIPBOARDUPDATE As Integer = &H31D

    <DllImport("User32.dll", SetLastError:=True)>
    Private Shared Function AddClipboardFormatListener(hwnd As IntPtr) As Boolean
    End Function

    <DllImport("User32.dll", SetLastError:=True)>
    Private Shared Function RemoveClipboardFormatListener(hwnd As IntPtr) As Boolean
    End Function

    Protected Overrides Sub OnHandleCreated(e As EventArgs)
        MyBase.OnHandleCreated(e)
        AddClipboardFormatListener(Me.Handle)
    End Sub

    Protected Overrides Sub OnHandleDestroyed(e As EventArgs)
        MyBase.OnHandleDestroyed(e)
        RemoveClipboardFormatListener(Me.Handle)        
    End Sub

    Protected Overrides Sub WndProc(ByRef m As Message)
        MyBase.WndProc(m)
        If m.Msg = WM_CLIPBOARDUPDATE Then
            GetClipboardContent()
        End If
    End Sub

    Private Sub GetClipboardContent()
        If Clipboard.ContainsImage() Then
            Dim clipboardImage As Image = Clipboard.GetImage()
            Dim nImageSize As Size = clipboardImage.Size           
        ElseIf Clipboard.ContainsData("PXCEditCbData") Then
            Dim dataObject As Object = Clipboard.GetData("PXCEditCbData")
            If TypeOf dataObject Is MemoryStream Then
                Dim stream As MemoryStream = DirectCast(dataObject, MemoryStream)
                ' BBox [0 0 6.237762 148.957275]
                Dim sResult As String = SearchForBBoxString(stream)
                Dim sValues As String = sResult.Substring(6, sResult.Length - 7)
                Dim sStringValues() As String = sValues.Split(" "c)
                Dim nValues(3) As Single
                For i As Integer = 0 To 3
                    nValues(i) = Single.Parse(sStringValues(i), CultureInfo.InvariantCulture)
                Next
            End If
        End If
    End Sub

    Private Function SearchForBBoxString(stream As MemoryStream) As String
        stream.Position = 0
        Dim reader As New StreamReader(stream, Encoding.ASCII)
        Dim sContent As String = reader.ReadToEnd()
        Dim nStartIndex As Integer = sContent.IndexOf("BBox [")
        If nStartIndex >= 0 Then
            Dim nEndIndex As Integer = sContent.IndexOf("]", nStartIndex)
            If nEndIndex > nStartIndex Then
                Dim sString As String = sContent.Substring(nStartIndex, nEndIndex - nStartIndex + 1)
                Return sString
            End If
        End If
        Return Nothing
    End Function  
End Class