System.Runtime.InteropServices.COMException：“此操作的不适当的源对象”。在检索连接的形状时识别

Question

我试图获取页面中每个形状的连接形状。但我发现一个奇怪的COM异常 - “此操作的不适当的源对象”

这是我的代码：

using Microsoft.Office.Interop.Visio;

class Program
{
  static void Main(string[] args)
  {
    Application visApp = new Application();
    Document visDoc = visApp.Documents.Open(filePath);

    // Get the first page in the sample drawing.
    page = visDoc.Pages[1];

    foreach (Microsoft.Office.Interop.Visio.Shape shp in page.Shapes)
    {               
        GetConnected(shp, Microsoft.Office.Interop.Visio.VisConnectedShapesFlags.visConnectedShapesOutgoingNodes, "", null, true);
    }
 }


    private static void GetConnected(Microsoft.Office.Interop.Visio.Shape shp, Microsoft.Office.Interop.Visio.VisConnectedShapesFlags whichConnectedShapes, string category, Microsoft.Office.Interop.Visio.Selection selection, bool addToSelection)
     {
        Array aryTargetIDs;

        //getting an exception here during the second iteration of for loop of Main method
        aryTargetIDs = shp.ConnectedShapes(whichConnectedShapes, category); 
     }
  }

Answer 1

ConnectedShapes方法抛出1D形状（即连接器）的此异常。因此，您只需要在调用助手方法之前或在其中包含此检查，如下所示：

using Visio = Microsoft.Office.Interop.Visio

private static void GetConnected(
            Visio.Shape shp, 
            Visio.VisConnectedShapesFlags whichConnectedShapes, 
            string category, 
            Visio.Selection selection, 
            bool addToSelection)
{
    if (shp is null)
    {
        throw new ArgumentNullException();
    }
    if (shp.OneD == 0)
    {   
        Array aryTargetIDs = shp.ConnectedShapes(whichConnectedShapes, category);
        Console.WriteLine($"{shp.Master.Name} ({shp.NameID}) - {String.Join(", ", aryTargetIDs.Cast<object>().ToArray())}");
    }
}

因此给出了一组这样的形状：

上面代码的控制台输出看起来像这样：

Start/End (Sheet.1) - 2
Decision (Sheet.2) - 4, 6
Subprocess (Sheet.4) - 
Document (Sheet.6) -