这个是数据库
Public Class Form3
Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim form1 As New Form1()
Dim myconn As New OleDb.OleDbConnection("Provider=Microsoft.ace.OLEDB.12.0;Data Source=D:\Documents\账号密码.accdb;")
Dim mystr As String
mystr = "select * from 表1,表2 where 表1.UserID=表2.UserID and 表2.UserID=" & form1.TextBox1.Text.Trim() & "'"
Dim myadapter As New OleDb.OleDbDataAdapter(mystr, myconn)
Dim mydataset As New DataSet
myadapter.Fill(mydataset, "表2")
Me.DataGridView1.DataSource = mydataset.Tables("表2")
End Sub
End Class
求解这顿代码怎么不能显示数据库的文件求解

你的这个没有报错？？ 那有就鬼了。
mystr = "select * from 表1,表2 where 表1.UserID=表2.UserID and 表2.UserID=" & form1.TextBox1.Text.Trim() & "'"
如果form1.TextBox1.Text.Trim()=11110
那这里转成SQL语句就是：select * from 表1,表2 where 表1.UserID=表2.UserID and 表2.UserID=11110‘
你说会不会报错？

问题找到了，Dim form1 As New Form1() 因为这个，你用了New 这个方式，你用form1.TextBox1.Text()去读Form1的控件值都被初始化了，所以是空的，那你的SQL语句变成了：select * from 表1,表2 where 表1.UserID=表2.UserID and 表2.UserID='‘
把这个Dim form1 As New Form1() 删除就行了。

mystr = "select * from 表1,表2 where 表1.UserID=表2.UserID and 表2.UserID=" & form1.TextBox1.Text.Trim() & "'"
把这个查询INTO到表3里，然后：
Dim adapter As OleDbDataAdapter = New OleDbDataAdapter("SELECT * FROM表3 ", dbConnection) '
Dim DataSet1 As DataSet = New DataSet()
adapter.Fill(DataSet1, "表3")
交易数据表.DataSource = DataSet1.Tables("表3")