C # Read the Excel file code and support multiple worksheets

Public Dataset exceltods ( String Filename)
{
String Connstr =   " Provider = Microsoft. Jet. oledb.4.0; "   + " Data Source = " + Filename + " ; " + " Extended properties = Microsoft Excel 8.0; " ;
String SQL _f =   " Select * from [{0}] " ;

Oledbconnection Conn =   Null ;
Oledbdataadapter da =   Null ;
Datatable tblschema =   Null ;
Arraylist tblnames =   New Arraylist ();

// Initialize the connection and open
Conn =   New Oledbconnection (connstr );
Conn. open ();

// Obtain the table definition metadata of the data source.
Tblschema = Conn. getoledbschematable (oledbschemaguid. Tables, New   Object [] {Null,Null,Null,"Table"} );

Foreach (Datarow row In Tblschema. Rows)
{
Tblnames. Add ((String) Row ["Table_name"]);//Read Table Name
}

// Initialize the adapter
Da =   New Oledbdataadapter ();
// Prepare data and import Dataset
Dataset DS =   New Dataset ();
Foreach ( String Tblname In Tblnames)
{
Da. selectcommand =   New Oledbcommand (string. Format (SQL _f, tblname), Conn );
Try  
{
Da. Fill (DS, tblname );

}
Catch  
{
// Close connection
If (Conn. State = Connectionstate. open)
{
Conn. Close ();
}
Throw ;
}
}
// Close connection
If (Conn. State = Connectionstate. open)
{
Conn. Close ();
}
Return DS;
}