在ms文档C#中使用backgroundworker时出错

Question

我正试图在MS word文档中使用进度条来显示循环操作进度，因此我在循环操作过程中使用了backgroundworker来更新进度条，如下代码所示。

  using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Linq;
  using System.Text;
  using System.Windows.Forms;
  using Word = Microsoft.Office.Interop.Word;
  using Microsoft.Office.Tools.Word;
namespace prog
{
public partial class PGB : Form
{
    public PGB()
    {
        InitializeComponent();
    }
    private static int Mx;
    private void PGB_Load(object sender, EventArgs e)
    {
        Mx = 100;
        PG.Maximum = Mx;
        PG.Step = 1;
        PG.Value = 0;
        BGW.RunWorkerAsync();
    }
    private void BGW_DoWork(object sender, DoWorkEventArgs e)
    {
        for (int j = 0; j <= Mx-1; j++)
        {
            Loop_Opt(j+1);
            BGW.ReportProgress((j));
        }
    }
    private void BGW_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        PG.Value = e.ProgressPercentage;
    }
    private void BGW_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        MessageBox.Show("Done");
    }
    public static void Loop_Opt(int n)
    {
        Word.Application wordApp;
        Word.Document oDoc = null;
        wordApp = (Word.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Word.Application");
        oDoc = wordApp.ActiveDocument;
        Document DD = Globals.Factory.GetVstoObject(oDoc);
        for (int i = 1; i <= oDoc.Bookmarks.Count; i++)
        {//loop operation//}
      }
  }
 }

发生错误的行是Loop_Opt（）类中的以下行：

   Document DD = Globals.Factory.GetVstoObject(oDoc);

错误消息如下：

      [Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.VisualStudio.Tools.Office.Runtime.Interop.IHostItemFactoryNoMAF'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{A0885C0A-33F2-4890-8F29-25C8DE7808F1}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).]

提前感谢

Answer 1

经过长时间的研究和试验，我认为使用后台工作人员控制并没有简单的解决方案。

因此，我使用了普通的方式来更新进度条，而不是像下面的代码中所示的background worker控件，它工作得很好，但与后台worker控件的效率不同。

public void Loop_Opt()
{
    Word.Application wordApp;
    Word.Document oDoc = null;
    wordApp = (Word.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Word.Application");
    oDoc = wordApp.ActiveDocument;
    Document DD = Globals.Factory.GetVstoObject(oDoc);
    PG.Maximum = oDoc.Bookmarks.Count;
    PG.Step = 1;
    PG.Value = 1;
    for (int i = 1; i <= oDoc.Bookmarks.Count; i++)
    {
       //loop operation//
       PG.PerformStep();
       Thread.Sleep(100);
       Application.DoEvents();
    }
  }

Answer 2

Office应用程序使用单线程单元模型（STA）。您不应该在辅助线程上使用它们。此外，Globals.Factory.GetVstoObject方法只能在基于VSTO的加载项中使用。

如果只处理开放式XML文档，我建议使用开放式XML SDK。或者使用任何其他第三方组件。