Excel COM對象強制轉換錯誤

Question

我試圖在代碼中避免使用“雙點”表示法（請參閱如何正確清理Excel互操作對象？ ）。 但是，當我嘗試更改以下代碼時出現錯誤

Excel.Workbook oWB;
...
oWB.Sheets[oWB.Sheets.Count].Delete();
oWB.Sheets[oWB.Sheets.Count].Delete();
oWB.Sheets[oWB.Sheets.Count].Delete();

對此

Excel.Sheets oS;
oS = oWB.Sheets;
//error occurs in the following line
oS = oWB.Sheets[oS.Count];
oS.Delete();
oS.Delete();
os.Delete();

錯誤是'Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Interop.Excel.Sheets'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000208D7-0000-0000-C000-000000000046}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).' 'Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Interop.Excel.Sheets'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000208D7-0000-0000-C000-000000000046}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).'

任何幫助表示贊賞。

Answer 1

您必須聲明一個Sheet類型的新變量。 oS的類型為Sheets ，而oS.Sheets[os.Count]的類型為Sheet （不帶最終的s）。 因為從運行時的角度來看它們是不相關的類型，所以必須聲明一個具有適當類型Sheet的中間變量。