The following code is not updating the excel file passed in the FileName parameter. No exceptions are being thrown.

public void UpdateExcelFile(string SomeFile)
{

OleDbConnection Connection = new OleDbConnection();

try{
OleDbCommand Command = new OleDbCommand();

string ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " + SomeFile + ";Extended Properties=Excel 8.0;";

Connection.ConnectionString = ConnectionString;
Connection.Open();

string MyCommandText = "UPDATE [Sheet1$A1:A1] SET F1 = 'SomethingNew'";

Command.CommandText = MyCommandText;

Command.Connection = Connection;

Command.ExecuteNonQuery();
}
catch(Exception ex)
{}
finally
{ Connection.Close() }
}