我怎么...我得到一个错误“0号位没有行”从这个vb.net代码 [英] How do i...i get an error "there is no row at position 0" from this vb.net code

问题描述

Imports System.Data.OleDb
Imports System.Data
Public Class WithdrawandDeposit2
    Dim adapt As New OleDbDataAdapter
    Dim dset As New DataSet
    Dim bal, num As String
    Dim total As Integer
    Function draw()
        cn = New OleDb.OleDbConnection
        With cn
            .ConnectionString = "Provider=Microsoft.Ace.OLEDB.12.0;Data Source=" & Application.StartupPath & "\Maccount.accdb"
            .Open()
        End With
        Dim dt As New DataSet("NewAccount")
        'Dim rs As New OleDb.OleDbDataAdapter(" Select Samount from NewAccount where Samount = '" + lblamount.Text + "'", cn)
        Dim rs As New OleDb.OleDbDataAdapter(" Select * from NewAccount where Saccountno = '" + TextBox1.Text + "'", cn)
        rs.Fill(dt)
        If .Tables(dt).rows.count > 0 Then
            bal = dt.Tables(0).Rows(0)(6).ToString()
            num = dt.Tables(0).Rows(0)(0).ToString()
            TextBox2.Text = dt.Tables(0).Rows(0)(2).ToString()
            Return 0
        End If
    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Val(WithBox.Text) > bal Then
            LowerBalance.Show()
        ElseIf Me.WithBox.Text = "" Then
            Errorform1.Show()
        Else
            total = bal - Val(WithBox.Text)
            Dim dbcommand As String = "update NewAccount set Samount = '" & total & "'where AccountName='" & TextBox1.Text & "'"
            adapt = New OleDbDataAdapter(dbcommand, cn)
            dset = New DataSet
            adapt.Fill(dset)
            'rs.Dispose()
            'cn.Close()
            Call draw()

        End If
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Close()
        Transactions.Show()
    End Sub

    Private Sub WithdrawandDeposit2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Call draw()
        TextBox2.Enabled = False
    End Sub
End Class

我尝试过：



i在bal = dt.tables（0）.rows（0）（6）中出错.ToString（）

What I have tried:

i am getting an error in bal = dt.tables(0).rows(0)(6).ToString()

推荐答案

它就像错误消息所说的那样简单：该表的行索引0处没有行。桌子是空的。在上面的一行，你似乎检查行数，但它显然是一个你在那里检查的不同的表。也许它看起来应该是这样的？：

It's as simple as the error message states: There is no row at row-index 0 of that table. The table is empty. At the line above you seem to check for the row count but it's apparently a different table you're checking there. Maybe it should look like this instead?:

If dt.Tables(0).Rows.Count > 0 Then

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