SQL Server Integration Services - How to check for the existence of an Excel Worksheet in SSIS

This code snippet shows you how to check for the existence of a worksheet in an Excel file. I had to do this because the data collection spreadsheet I was importing from would not add a $Warnings worksheet if there were no warnings for a particular set of data. The code below relies on the GetSchema() method of OLEDB connections to obtain schema information.

public class ScriptMain
{
    public void Main()
        {
            string fileToTest;
            string tableToTest;
            string connectionString;
            OleDbConnection excelConnection;
            DataTable excelTables;
            string currentTable;

            fileToTest = Dts.Variables["ExcelFile"].Value.ToString();
            tableToTest = Dts.Variables["ExcelTable"].Value.ToString();

            Dts.Variables["ExcelTableExists"].Value = false;
            if (File.Exists(fileToTest))
            {
                connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
                "Data Source=" + fileToTest + ";Extended Properties=Excel 8.0";
                excelConnection = new OleDbConnection(connectionString);
                excelConnection.Open();
                excelTables = excelConnection.GetSchema("Tables");
                foreach (DataRow excelTable in excelTables.Rows)
                {
                    currentTable = excelTable["TABLE_NAME"].ToString();
                    if (currentTable == tableToTest)
                    {
                        Dts.Variables["ExcelTableExists"].Value = true;
                    }
                }
            }

            Dts.TaskResult = (int)ScriptResults.Success;

        }
}

For more information, see http://technet.microsoft.com/en-us/library/ms403358.aspx#example1