Update Database using DataSet

[k3nTm]

Good day!!!
can you help me with my code on whats wrong with it. I want to update my MSSQLSERVER database from a DataSet. and there's nothing happen with my
Database.

Here is my code:

string ConnString = "Data Source=localhos t\\sqlexpress;I nitial Catalog=dbSampl e;Integrated Security=SSPI";
string SelectData = "SELECT * FROM TblIndex";
int added = 0;

SqlConnection sqlconn = new SqlConnection(C onnString);
SqlCommand sqlcmd = new SqlCommand(Sele ctData, sqlconn);
SqlDataAdapter sqladapt = new SqlDataAdapter( sqlcmd);
SqlCommandBuild er sqlbuild = new SqlCommandBuild er(sqladapt);
DataSet _ds = new DataSet();
_ds.Tables.Add( );
_ds.Tables[0].Columns.Add();

_ds.Tables[0].Rows.Add();
_ds.Tables[0].Rows[0][0] = "a";
_ds.Tables[0].Rows.Add();
_ds.Tables[0].Rows[1][0] = "b";


try
{
sqlconn.Open();
sqladapt.Fill(_ ds);
added = sqladapt.Update (_ds);
}
catch (Exception ex)
{
Response.Write( ex.Message);
}
finally
{
sqlconn.Close() ;
}

if (added > 0)
{
lblItems.Text = "Add complete.";
}

please help me... :-)