1

我在尝试使用 VB.NET 从 MySQL 数据库中读取数据时遇到问题，我收到的错误消息是“ArgumentExcpetion 未处理”

此外，读数应返回“F”，因为这是分配在桌子上特定位置的值。

Imports MySql.Data.MySqlClient
Public Class Form1
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Application.Exit()
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim query As String = "SELECT DO FROM klein WHERE COMMAND='DELETE'"
        Dim connStr As String = "server=" & TextBox1.Text & ";" _
            & "user id=" & TextBox2.Text & ";" _
            & "password=" & TextBox3.Text & ";" _
            & "database=hidro201_liberato"
        Dim connection As New MySqlConnection(connStr)
        Dim cmd As New MySqlCommand(query, connection)
        connection.Open()
        Dim reader As MySqlDataReader
        reader = cmd.ExecuteReader()
        While reader.Read()
            TextBox4.Text = (reader.GetChar(1))   '<- **problem is here**
        End While
    End Sub
End Class
4

3 回答 3

1

字段索引从零开始。

TextBox4.Text = (reader.GetChar(0))

http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.getchar.aspx

参数 i：“从零开始的列序号。”

于 2012-10-31T23:01:06.057 回答
0

您的查询中只有一列，该列的索引应为零

TextBox4.Text = (reader.GetChar(0))

这适用于 SqlServer，但规则与 MySqlDataReader 相同

于 2012-10-31T23:01:34.810 回答
0

TextBox4.Text = (reader.GetChar("获取值的列名")) 万事如意

于 2013-04-29T11:02:01.293 回答