Question

I have a checkedlistbox and I want to drag and drop only image extensions and not text files.
so how do I get it done.
I am able to drag and drop all file formats but I need only image files.
Here is my code:

Private Sub CheckedListBox1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles CheckedListBox1.DragDrop

    Dim Files As String() = CType(e.Data.GetData(DataFormats.FileDrop), String())
    For Each FileName As String In Files
        CheckedListBox1.Items.Add(FileName, CheckState.Checked)
        Thumbcontrol1.AddThumbnail(FileName)
    Next
End Sub

Private Sub CheckedListBox1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles CheckedListBox1.DragEnter
    If e.Data.GetDataPresent(DataFormats.FileDrop) Then
        e.Effect = DragDropEffects.Copy
    End If
End Sub

Answer 1

Just check each file name’s extension.

Private Shared ReadOnly SupportedExtensions As String() = {".jpg", ".jpeg", ".gif"}

Private Sub CheckedListBox1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles CheckedListBox1.DragDrop
    Dim Files As String() = CType(e.Data.GetData(DataFormats.FileDrop), String())
    For Each FileName As String In Files
        Dim Extension As String = Path.GetExtension(FileName).ToLower
        If Array.IndexOf(SupportedExtensions, Extension) <> -1 Then
            CheckedListBox1.Items.Add(FileName, CheckState.Checked)
            Thumbcontrol1.AddThumbnail(FileName)
        End If
    Next
End Sub

You may want to add similar code to the DragEnter method to show DragDropEffects.None if there are no picture files in the dragged file list.