private void menuContext_Popup(object sender, EventArgs e) { bool bEnable = _DrawPanel.SelectedCount <= 0? false: true; menuCopy.Enabled = bEnable; menuDelete.Enabled = bEnable; List<XmlNode> al=new List<XmlNode>(); IDataObject iData = Clipboard.GetDataObject(); if (iData == null) bEnable = false; else if (iData.GetDataPresent(al.GetType())) bEnable = true; else if (iData.GetDataPresent(DataFormats.Text)) bEnable = true; else if (iData.GetDataPresent(DataFormats.Bitmap)) bEnable = true; else bEnable = false; menuPaste.Enabled = bEnable; return; }