title: specified cast is not available
body: <p>can someone help me in this code please</p>
  
  <p>is says specified cast is not available</p>
  
  <pre><code>MysqlConn = New SqlConnection
      MysqlConn.ConnectionString =
          "Data Source=SABAHALI-SHEIKH;Initial Catalog=md_1103763;Integrated Security=True"
      Dim READER As SqlDataReader
  
      Try
          MysqlConn.Open()
          Dim Query As String
          Query = "SELECT [firstname] FROM md_1103763.dbo.customer where firstname='" &amp; ComboBox1.Text &amp; "'"
          COMMAND = New SqlCommand(Query, MysqlConn)
          READER = COMMAND.ExecuteReader
          While READER.Read
              TextBox1.Text = READER.GetInt32("customerID")
              TextBox2.Text = READER.GetString("firstname")
              TextBox3.Text = READER.GetString("surname")
              TextBox4.Text = READER.GetString("contactnumber")
              TextBox5.Text = READER.GetString("emailaddress")
  
          End While
  
          MysqlConn.Close()
  
      Catch ex As Exception
          MessageBox.Show(ex.Message)
      Finally
          MysqlConn.Dispose()
  
  
      End Try
  </code></pre>