javascript - ASP.NET 自定义验证器客户端和服务器端验证

Question

在我的网页中，我尝试在客户端和服务器端执行验证。如果下拉菜单和文本框为空，我需要显示一条错误消息，但如果其中之一已填写，则验证应该通过。有没有办法为这两个控件创建一个 CustomValidator？我感觉我做得不对。

客户端代码:

 <div>
        <table>
            <tr>
                <td>
                 <asp:DropDownList ID="ddlStates" runat="server"  Width="128px">
                             <asp:ListItem></asp:ListItem>
                             <asp:ListItem>Nevada</asp:ListItem>
                             <asp:ListItem>Uta</asp:ListItem>
                             <asp:ListItem>Oregon</asp:ListItem>
                  </asp:DropDownList>
                </td>
                 <td>
                     <asp:CustomValidator ID="cvddlState" runat="server"
                     ClientValidationFunction="StatesCheck"
                     OnServerValidate="ServerValidation"
                     ErrorMessage="(*) State is required" ForeColor="Red"
                     Display="Dynamic"></asp:CustomValidator>
                </td>

            </tr>
            <tr>
                <td>
                    <asp:TextBox ID="txtStates" runat="server"></asp:TextBox>
                </td>
                <td>
                    <asp:CustomValidator ID="cvtxtStates" runat="server"
                     ValidateEmptyText="true"
                     ClientValidationFunction="StatesCheck"
                     OnServerValidate="ServerValidation"
                     ControlToValidate="txtStates"
                     ErrorMessage="(*) Text cannot be empty" ForeColor="Red"
                     Display="Dynamic"></asp:CustomValidator>
                </td>

            </tr>
            <tr>
                <td>
                      <asp:Button  ID="btnSubmit" runat="server" Text="Submit" />
                </td>
            </tr>
        </table>
    </div>

     <div id="divErrorMessage" runat="server" class="alert alert-danger" visible="false"></div>
 

<script type="text/javascript">

    'Use Strict';
    function StatesCheck(source, args) {
        var ddlStates = document.getElementById("<%=ddlStates.ClientID%>");
        var txt = document.getElementById('<%=txtStates.ClientID%>').value;
        var state = ddlStates.options[ddlStates.selectedIndex].value;

        if (ddlStates !== null) {
            if ((state === "") && (txt === "")) {
                args.IsValid = false;
            }
            else {
                args.IsValid = true;
            }
        }
    }

</script>

服务器端代码:

Public Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
        Try
            divErrorMessage.Visible = False
            divErrorMessage.InnerText = ""


            Dim ddlSelection As String = ddlStates.SelectedItem.Text
            Dim statesText As String = txtStates.Text.Trim()
            If statesText = String.Empty And ddlSelection = String.Empty Then
            Else
                divErrorMessage.Visible = True
                divErrorMessage.InnerText = "(*) Text cannot be empty"
            End If

        Catch ex As Exception

        End Try
    End Sub

    Protected Sub ServerValidation(source As Object, args As ServerValidateEventArgs)
        If (ddlStates.SelectedItem.Text = String.Empty) And (txtStates.Text.Length = 0) Then
            args.IsValid = False
        Else
            args.IsValid = True
        End If

    End Sub

Answer 1

您是否从服务器端和客户端的代码中得到答案？我想回答服务器端

Protected Sub ServerValidation(source As Object, args As ServerValidateEventArgs)
        If (ddlStates.SelectedItem.Text = String.Empty) And (txtStates.Text.Length = 0) Then
            args.IsValid = False
        Else
            args.IsValid = True
        End If

    End Sub

根据我的经验，我不太擅长 ASP.net，但根据上面的 ypur 代码，没有任何问题，但是你所说的部分 但是如果填写其中之一，验证应该通过 此处未显示，您可以尝试执行此操作吗？

 Protected Sub ServerValidation(source As Object, args As ServerValidateEventArgs)
            If (ddlStates.SelectedItem.Text = String.Empty) Or (txtStates.Text.Length = 0) Then
                args.IsValid = False
Else
                args.IsValid = True
            End If

        End Sub

或者也许

Protected Sub ServerValidation(source As Object, args As ServerValidateEventArgs)
        If (ddlStates.SelectedItem.Text = String.Empty) And (txtStates.Text.Length = 0) Then
            args.IsValid = False
        ElseIf (ddlStates.SelectedItem.Text <> String.Empty) then
          args.IsValid = True
        ElseIf (txtStates.Text <> "") then
          args.IsValid = True
        Else

            args.IsValid = True
        End If

    End Sub