mysql - 从字符串到整数的转换错误

Question

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    ListBox1.Items.Clear()

    sql = "SELECT * FROM testing_mysql_vb"
    Try
        dbcomm = New MySqlCommand(sql, dbconn)
        dbread = dbcomm.ExecuteReader()

        While dbread.Read
            ListBox1.Items.Add(dbread("product_name")("product_quantity"))
        End While

        dbread.Close()
    Catch ex As Exception
        MsgBox("Error in collecting data from Database. Error is :" & ex.Message)
        dbread.Close()
        Exit Sub
    End Try
End Sub
End Class

我无法从我的数据库中获取数据。

它说从字符串到整数的转换出错。

Answer 1

您正在将 dbread("product_name")("product_quantity") 传递给 ListBox.Items.Add。那是行不通的。也许您想合并两列:

Dim prodNameVal As Object = dbread("product_name")
Dim productQuantityValue As Object = dbread("product_quantity")
ListBox1.Items.Add(String.Format("{0}: {1}", prodNameVal, productQuantityValue))