Excel “External table is not in the expected format.” .

Question:

I'm trying to read an Excel (xlsx) file using the code shown below. I get an "External table is not in the expected format." error unless I have the file already open in Excel. In other words, I have to open the file in Excel first before I can read if from my C# program. The xlsx file is on a share on our network. How can I read the file without having to open it first? Thanks

 string sql = "SELECT * FROM [Sheet1$]";  string excelConnection = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + pathname + ";Extended Properties=/"Excel 8.0;HDR=YES;IMEX=1;/"";    using (OleDbDataAdapter adaptor = new OleDbDataAdapter(sql, excelConnection)) {  DataSet ds = new DataSet();  adaptor.Fill(ds);  }  

Answers:

"External table is not in the expected format." typically occurs when trying to use an Excel 2007 file with a connection string that uses: Microsoft.Jet.OLEDB.4.0 and Extended Properties=Excel 8.0

Using the following connection string seems to fix most problems.

 public static string path = @"C:/src/RedirectApplication/RedirectApplication/301s.xlsx";  public static string connStr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=Excel 12.0;";
以上出处：http://blog.csdn.net/ldl22847/article/details/6322339

//2003（Microsoft.Jet.Oledb.4.0）
string strConn = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'", excelFilePath);

//2007（Microsoft.ACE.OLEDB.12.0）
string strConn = string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'", excelFilePath);