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=localhost\\sqlexpress;Initial Catalog=dbSample;Integrated Security=SSPI";
string SelectData = "SELECT * FROM TblIndex";
int added = 0;

SqlConnection sqlconn = new SqlConnection(ConnString);
SqlCommand sqlcmd = new SqlCommand(SelectData, sqlconn);
SqlDataAdapter sqladapt = new SqlDataAdapter(sqlcmd);
SqlCommandBuilder sqlbuild = new SqlCommandBuilder(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... :-)