asp.net – CustomValidator不工作

我有一个CustomValidator,用于检查在文本框中输入的文本是否与数据库中的某些字段匹配.这之前一切都很好,但是从那时起我已经修改了很多页面并且它已经不再有效了.我不认为我改变了会影响这一点的任何事情,但显然我做了.我所有其他验证器(必需的字段验证器)都正常工作,但我的CustomValidator没有响应.

所以无论如何,这是我的代码：

的CustomValidator：

<asp:CustomValidator ID="CustomValidator1" runat="server" ControlToValidate="txtCoursePrefix" ErrorMessage="Course number is already taken."></asp:CustomValidator>

VB代码隐藏：

Protected Sub CustomValidator1_ServerValidate(ByVal source As Object,ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CustomValidator1.ServerValidate

    'Checking for duplicate course numbers

    'get values
    Dim checkPrefix = txtCoursePrefix.Text
    Dim checkNum = txtCourseNum.Text

    'db connectivity
    Dim myConn As New OleDbConnection
    myConn.ConnectionString = AccessDataSource2.ConnectionString
    myConn.Open()

    'select records
    Dim mySelect As New OleDbCommand("SELECT 1 FROM tableCourse WHERE prefix=? AND course_number=?",myConn)
    mySelect.Parameters.AddWithValue("@checkPrefix",checkPrefix)
    mySelect.Parameters.AddWithValue("@checkNum",checkNum)

    'execute(Command)
    Dim myValue = mySelect.ExecuteScalar()

    'check if record exists
    If myValue IsNot Nothing Then
        CustomValidator1.SetFocusOnError = True
        args.IsValid = False
    End If

End Sub

一切正常,直到CustomValidator1.SetFocusOnError = True且args.IsValid = False.我已经测试了If语句并且它正常工作,它返回true并且我放入其中的任何其他内容都会执行.

function customClientValidationFunction(sender,arguments) {
   arguments.IsValid = true; //validation goes here
}