VB.NET中的DataGrid绑定错误

liontown 2002-05-30 08:00:50

在我的程序中的倒数第二行有错
显示未处理的“System.Data.OleDb.OleDbException”类型的异常出现在 system.data.dll 中
请大家救救我把!谢谢!
程序源码如下
Imports System.Data
'引入数据库操作类命名空间
Imports System.Data.OleDb
'引入ADO.NET操作命名空间
Dim ADOcmd As OleDbDataAdapter
'建立ADODataSetCommand对象
Dim ds As DataSet = New DataSet()
'建立DataSet对象
Dim mytable As Data.DataTable
'建立表单对象
Dim myrow As Data.DataRow
Dim mydb As DAO.Database
Dim myws As DAO.Workspace
Dim mysql As String
Dim myrec As DAO.Recordset
Dim de As DAO.DBEngine = New DAO.DBEngine()
Friend WithEvents Student2 As stu.student

Dim rownumber As Integer
'定义一个整型变量来存放当前行数
Public Function OpenDb() As Short
Dim SQLstr As String
'定义SQL查询字符串
SQLstr = "c:\db2.mdb"
'建立SQL查询语句
myws = de.Workspaces(0)
mydb = myws.OpenDatabase(SQLstr, False, False)
SQLstr = "select * from tblstudent"
myrec = mydb.OpenRecordset(SQLstr, DAO.RecordsetTypeEnum.dbOpenDynaset)
'建立ADODataSetCommand对象
ADOcmd.Fill(ds, "tblstudent")
'取得表单
mytable = ds.Tables.Item(0)
'取得tblbooks表
rownumber = 0
'设置为起始行
myrow = mytable.Rows.Item(rownumber)
'取得第1行数据
End Function

按钮事件

Dim SearchSQLStr As String
'定义查询字符串
Dim Searchcmd As OleDbDataAdapter
'定义查询用ADODataSetCommand对象
Dim searchds As DataSet = New DataSet()
'定义查询DataSet对象
SearchSQLStr = "select *" & _
"from tblstudent" & _
"where username = '" & txt.Text & "'"
Searchcmd = New OleDbDataAdapter(SearchSQLStr, "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\db2.mdb")
Searchcmd.Fill(searchds, "tblstudent")
DataGrid1.DataSource = searchds.Tables.Item(0).DefaultView

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