mysql - vb.net/mysql在TextBox中显示1行以上

我刚开始弄乱Visual Basic（vb.net），并试图在TextBox中显示多于1个数据库行，到目前为止，我有这个：

Private Sub foobox_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

        Dim conn As MySqlConnection

        conn = New MySqlConnection
        conn.ConnectionString = connStr

        Try
            conn.Open()
        Catch myerror As MySqlException
            MsgBox("No connection")
        End Try

        Dim myAdaptor As New MySqlDataAdapter

        Dim sqlquery = "SELECT * FROM foo ORDER BY id DESC"
        Dim myCommand As New MySqlCommand()
        myCommand.Connection = conn
        myCommand.CommandText = sqlquery

        myAdaptor.SelectCommand = myCommand
        Dim myData As MySqlDataReader
        myData = myCommand.ExecuteReader()

        If myData.HasRows Then
            myData.Read()
            Viewer.Text = myData("foo1") & myData("foo2")

        End If

        myData.Close()
        conn.Close()

    End Sub

哪个成功连接到数据库，但只输出1行，如何获取更多行呢？

最佳答案

您需要一个循环读取数据并在StringBuilder中逐行存储。
然后，从阅读循环退出时，设置文本框的Text属性

    Dim sb as StringBuilder = new StringBuilder()
    While myData.Read()
        sb.AppendLine(myData("foo1") & myData("foo2"))
    End While
    Viewer.Text = sb.ToString

并且，当然，您的文本框应将MultiLine属性设置为True

除了直接回答您的问题之外，还应在使用后更改您的代码以处理连接和数据读取器，我也删除了DataAdapter，因为这里不需要

    Using conn = New MySqlConnection(connStr)
        Try
            conn.Open()
        Catch myerror As MySqlException
            MsgBox("No connection")
        End Try

        Dim sqlquery = "SELECT * FROM foo ORDER BY id DESC"
        Dim myCommand As New SqlCommand(sqlquery, conn)
        Using myData = myCommand.ExecuteReader()
            Dim sb as StringBuilder = new StringBuilder()
            While myData.Read()
                sb.AppendLine(myData("foo1") & myData("foo2"))
            End While
            Viewer.Text = sb.ToString
        End Using
    End Using