Why setting OLEDBConnection.Connection throws Exception (HRESULT: 0x800A03EC)?

问题

I am working with Excel Interop namespace to modify connection string in the Excel Workbook connections.

Why when I am trying to set the connection property (MSDN OLEDBConnection.Connection) throws an error on the line of the assignment?

Exception from HRESULT: 0x800A03EC

application = new Application();
Workbook wb = application.Workbooks.Open(file.FullName);
Sheets wbs = wb.Worksheets;
IEnumerable<Workbook> workbooks = application.Workbooks.Cast<Workbook>();

foreach (var connection in wb.Connections.Cast<WorkbookConnection>()
    .Where(c => c.Type == XlConnectionType.xlConnectionTypeOLEDB))
{
    connection.OLEDBConnection.Connection = "Test Connection String";
}

application.Quit();

However, calling Replace method as shown below is working. I have found this as workaround, not being sure why Replace works in this case.

application = new Application();
Workbook wb = application.Workbooks.Open(file.FullName);
Sheets wbs = wb.Worksheets;
IEnumerable<Workbook> workbooks = application.Workbooks.Cast<Workbook>();

foreach (var connection in wb.Connections.Cast<WorkbookConnection>()
    .Where(c => c.Type == XlConnectionType.xlConnectionTypeOLEDB))
{
    var conString = connection.OLEDBConnection.Connection.ToString();
    connection.OLEDBConnection.Connection = 
        conString.Replace("Test Connection String", "New Test Connection String");
}

application.Quit();

This in fact is the only way I could get the connection string changed, therefore asking what is the reason behind why set could be throwing the error.

回答1:

There could be many reasons. The common of all being backwards compatibility. Such as XLS file being opened.

Also normalize the full file path - use backslashes. Set DefaultSaveFormat to xlOpenXML or something similar on 'application' if you are sure that you are not operating on a file created with older version of Excel.

The COM error with the code you specified, is generally thrown when it cannot resolve the object name - within the Workbook - or it has any other problem in resolution of such names.

If these fail, check this link:

http://www.hagrin.com/319/exception-hresult-0x800a03ec-excel-net-sql-and-windows-server-2008

回答2:

I found a way to use the OpenXML instead, seems that changing connection string via interop was not the only way.

using (SpreadsheetDocument excelDoc = SpreadsheetDocument.Open(file.FullName, true))
{
    WorkbookPart workbookpart = excelDoc.WorkbookPart;
    ConnectionsPart connPart = workbookpart.ConnectionsPart;

    string spreadsheetmlNamespace = @"http://schemas.openxmlformats.org/spreadsheetml/2006/main";
    NameTable nt = new NameTable();
    XmlNamespaceManager nsManager = new XmlNamespaceManager(nt);
    nsManager.AddNamespace("sh", spreadsheetmlNamespace);

    XmlDocument xdoc = new XmlDocument(nt);
    xdoc.Load(connPart.GetStream());

    XmlNode oxmlNode = xdoc.SelectSingleNode("/sh:connections/sh:connection/sh:dbPr/@connection", nsManager);
    string newConnection = ReplaceInitialCatalog(oxmlNode.Value, repConfig.DbName);
    oxmlNode.Value = oxmlNode.Value.Replace(oxmlNode.Value, newConnection);

    //Truncates part with FeedData
    connPart.FeedData(connPart.GetStream());
    xdoc.Save(connPart.GetStream());
}

回答3:

Issue was that connection string seem to have special prefix (OLEDB;) which is checked upon the assignment so it can be solved by this:

...
connection.OLEDBConnection.Connection = "OLEDB;Test Connection String";
...

Prefix showed its face upon connection string retrieval, thus the clue.

Though recommend OpenXML due to ease of testability.

来源：https://stackoverflow.com/questions/38302778/why-setting-oledbconnection-connection-throws-exception-hresult-0x800a03ec

标签

excel

connection-string

office-interop