vb如何读取数据库一行数据？

'读取方法：

Imports System.IO

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Me.ListBox1.Items.Clear()

Dim StrRed As StreamReader = New StreamReader("D:\111.txt", System.Text.Encoding.Default)

While Not StrRed.EndOfStream

Me.ListBox1.Items.Add(StrRed.ReadLine())

End While

StrRed.Dispose()

End Sub

End Class

'其它读写方法：

写入：

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

Dim strR As New StreamWriter("D:\111.txt", True)'参数True表示 在原来的数据上面添加，如果为False这删除原来的数据 重新写入数据

strR.WriteLine(Me.TextBox2.Text)

strR.Dispose()

End Sub

读取：

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

Dim strR As New StreamReader("D:\111.txt")

While Not strR.EndOfStream

Me.TextBox1.Text += strR.ReadLine() &vbCrLf

End While

strR.Dispose()

End Sub

'1.首先"工程"-"引用"---"Microsoft Script Runtime"

'2.将text2 的multiline属性设置为true ScrollBars 属性设置为2-Vertical

Dim fso As New FileSystemObject

Private Sub Form_Load()

Text1.Text = ""

Text2.Text = ""

If fso.FileExists("c:\abc.txt") Then '判断文件是否存在

Dim sum_row As Integer

sum_row = 1

Open "c:\abc.txt" For Input As #7

Line Input #7, first_row '按行读取

Text1.Text = first_row

Do While Not EOF(7)

Line Input #7, next_row

sum_row = sum_row + 1

If sum_row >50 Then

Exit Do

Else

Text2.Text = Text2.Text &next_row &vbCrLf

End If

Loop

Close #7

Else

MsgBox "您指定目录下的文件不存在!", vbInformation + vbOKOnly, "信息提示"

End If

End Sub

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