You need to take a datagidview say datagridview1 and
apply the following
1)generate the combobox_selectedindexchange event and write the following code
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection sqlConn = new SqlConnection("Data Source=;Initial Catalog=" + "Integrated Security=SSPI");
SqlCommand sqlCmd = sqlConn.CreateCommand();
sqlCmd.CommandText = ("Select * From "+ comboBox1.SelectedText);
SqlDataAdapter da=new SqlDataAdapter(sqlCmd);
DataSet ds=new DataSet();
da.Fill(ds);
datagridview1.DataSource=ds.Tables[0];
}