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

Question

我正在尝试获取页面中每个形状的连接形状。但是我发现一个奇怪的COM异常-“此操作不适当的源对象”

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方法对一维形状（即连接器）抛出此异常。因此，您只需要在调用助手方法之前或按照以下说明在其中包括此检查即可：

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，给定一组这样的形状：

以上代码的控制台输出如下所示：

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