javascript - 按钮的单击在后面运行代码并且不回发页面(刷新)asp.net

Question

我的登录时遇到下拉菜单问题。当我按下登录链接时，下拉菜单会向下滑动。我想要的是当错误的凭据被提供给不回发(刷新)时，下拉菜单将保持打开状态，以便用户输入正确的密码!

我尝试过 OnClientClick="return false;"但这会禁用我的 asp:button 的 onclick 事件。

我的代码:

string insCmd = "SELECT ID_USER FROM users WHERE username = @LoginEmail AND password = @passwd;";
        SqlCommand Login = new SqlCommand(insCmd, con);

        Login.Parameters.AddWithValue("@LoginEmail", txtLoginEmail.Text);
        Login.Parameters.AddWithValue("@passwd", txtLoginPassword.Text);

        try
        {
            SqlDataReader dr = Login.ExecuteReader();
            SqlDataReader dr2;

            if (dr == null || !dr.HasRows)
            {
                litErrorLogin.Text = "<span>Error:Wrong Credentials</span>";

                //btnLogin.OnClientClick = "return false;";
                return;
            }

            while (dr.Read())
            {
                Session["UserID"] = dr.GetInt32(0);
            }

我的html代码:

<div id="bb_loginForm">
    <div class="bg_loginForm">
        <span style="font-size:11.5px;font-weight:bold">Log in to Account</span> <a class="bb_linkLoginHeaderHide" href="#" title="Hide">
            Hide</a>
        <br />
        <div class="f_username">
            <label for="txtLoginEmail" id="labelUser">
                Email
            </label>
            <br />
            <asp:TextBox class="text-input" ID="txtLoginEmail" runat="server" Height="15px" Width="130px"></asp:TextBox>
        </div>

        <div class="f_password">
            <label for="txtLoginPassoword" id="labelPassword">
                Password
            </label>
            <br />
            <asp:TextBox class="text-input" ID="txtLoginPassword" runat="server" Height="15px" Width="130px" 
                TextMode="Password"></asp:TextBox>
        </div>
        <br />
        <div class="f_login">

            <!--src="../images/GreyButton.png"   class="submit btn primary-btn" onclick="btnLogin_Click"-->
            <asp:Button class="submit google-button" ID="btnLogin" onclick="btnLogin_Click" runat="server" Text="Log in" />                                       


            <br />

            <asp:CheckBox ID="chkRememberLogin" runat="server" />
            &nbsp;
            <label class="smaller" for="chkRememberLogin" id="labelrememberusername">Remember me
            </label>
            <br />
            <a title="Forgot your login info?" href="#" class="underlineHover">Forgot your login
                info? </a>
            <br />
            <asp:Literal ID="litErrorLogin" runat="server"></asp:Literal>
        </div>
    </div>
</div>

Answer 1

您可以基于Ajax进行开发为了不发布所有页面，而只发布页面的一部分。 (更新部分页面)

        <asp:ScriptManager ID="ScriptManager1" runat="server" />
        <asp:UpdatePanel runat="server" id="UpdatePanel" updatemode="Conditional">
        <Triggers>
            <asp:AsyncPostBackTrigger controlid="btnLogin" eventname="Click" />
        </Triggers>
            <ContentTemplate>
                <asp:Literal ID="litErrorLogin" runat="server"></asp:Literal>   
                <asp:Button class="submit google-button" ID="btnLogin" onclick="btnLogin_Click" runat="server" Text="Log in" />                                       

            </ContentTemplate>
        </asp:UpdatePanel>

您设置了所有不想在 ContentTemplate 之外发布的控件

注意:我已修复updatemode="Conditional"和<asp:AsyncPostBackTrigger controlid="btnLogin" eventname="Click" />