Question

我检查了每个参数，仍然无法获得Invalid操作异常并突出显示代码 da.Fill（ds）。请帮帮我。

连接模块：

Imports System.Data
Imports System.Data.SqlClient


Module Connectionmodule
    Public constr As String
    Public con As SqlConnection
    Public usertype As String
    Public Sub myconnection()
        constr = "server=KARAN-PC;database=Karan;trusted_connection=yes"
        con = New SqlConnection(constr)
        con.Open()
    End Sub
End Module

登录表格：

导入System.Data Imports System.Data.SqlClient

公共类LoginForm Dim da As SqlDataAdapter Dim ds As DataSet Dim query As String

Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
    query = "select * from usermaster where username = '" & username.Text & "' and password = '" & password.Text & "'"
    da = New SqlDataAdapter(query, con)
    ds = New DataSet
    da.Fill(ds)

    If ds.Tables(0).Rows.Count > 0 Then
        usertype = ds.Tables(0).Rows(0).Item(2)
        MsgBox(usertype)
        MsgBox(usertype)

    Else
        MsgBox("In Valid user")
    End If
    Me.Close()

End Sub


Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
    Me.Close()
End Sub

结束班

vb.net中无效的操作异常无效

0 个答案: