当我使用组合框选择表名并且它不起作用并显示错误消息为＆＃34;转换字符串到long类型无效＆＃34;。有人帮我吗？
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogin.Click
lblError1.Text = ""
lblError2.Text = ""
Dim con As New OleDb.OleDbConnection
Dim str As String = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=..\VisitorPass.accdb"
con = New OleDbConnection(str)
Dim sql As String = "select AccountName,[Password] from [" & ComboBox1.SelectedItem.trim().ToString() & "] where AccountName='" & txtName.Text.Trim().ToString() & "'and [Password]='" & txtPassword.Text.Trim().ToString() & "'"
Dim cmd As OleDbCommand
Dim dr As OleDbDataReader
Dim obj As New VisitorProfile
cmd = New OleDbCommand(sql, con)
con.Open()
dr = cmd.ExecuteReader()
Try
If txtName.Text.Trim().ToString() = "" Then
lblError2.Text = ""
lblError1.Text = "pls write name"
ElseIf txtPassword.Text.Trim().ToString() = "" Then
lblError1.Text = ""
lblError2.Text = "pls write password"
'ElseIf Not dr.HasRows = txtName.Text.Trim() Then
' lblError1.Text = "your Account is incorrect"
' ElseIf Not dr.HasRows = txtPassword.Text.Trim() Then
' lblError2.Text = "your Password is incorrect"
ElseIf Not ComboBox1.SelectedItem.ToString() Then
MsgBox("Sorry Please try again !", MsgBoxStyle.OkOnly, "Invalid Login")
ElseIf Not dr.HasRows Then
MsgBox("Sorry Please try again !", MsgBoxStyle.OkOnly, "Invalid Login")
ElseIf dr.Read Then
txtName.Text = dr("AccountName").ToString()
txtPassword.Text = dr("Password").ToString()
obj.StringPass = txtName.Text
MsgBox("welcome")
obj.Show()
VisitorProfile.lblwelcome.Text = txtName.Text
Me.Hide()
Else
con.Close()
MsgBox("Sorry Please try again", MsgBoxStyle.OkOnly, "invalid login")
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub