javascript - 更新时如何使用javascript验证asp.net gridview文本框？

Question

我的 aspx 页面上有一个 gridview:

<asp:GridView ID="gvPhoneBook" runat="server" AutoGenerateColumns="false" 
            ShowFooter="true" DataKeyNames="PhoneBookID"
            ShowHeaderWhenEmpty="true"

            OnRowCommand="gvPhoneBook_RowCommand" 
            OnRowEditing="gvPhoneBook_RowEditing" OnRowCancelingEdit="gvPhoneBook_RowCancelingEdit"
            OnRowUpdating="gvPhoneBook_RowUpdating" OnRowDeleting="gvPhoneBook_RowDeleting">

            <Columns>
                <asp:TemplateField HeaderText="First Name">
                    <ItemTemplate>
                        <asp:Label Text='<%# Eval("FirstName") %>' runat="server" />
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="txtFirstName" Text='<%# Eval("FirstName") %>' runat="server" />
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtFirstNameFooter" runat="server" />
                    </FooterTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Last Name">
                    <ItemTemplate>
                        <asp:Label Text='<%# Eval("LastName") %>' runat="server" />
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="txtLastName" Text='<%# Eval("LastName") %>' runat="server" />
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtLastNameFooter" runat="server" />
                    </FooterTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Contact">
                    <ItemTemplate>
                        <asp:Label Text='<%# Eval("Contact") %>' runat="server" />
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="txtContact" Text='<%# Eval("Contact") %>' runat="server" />
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtContactFooter" runat="server" />
                    </FooterTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Email">
                    <ItemTemplate>
                        <asp:Label Text='<%# Eval("Email") %>' runat="server" />
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="txtEmail" Text='<%# Eval("Email") %>' runat="server" />
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtEmailFooter" runat="server" />
                    </FooterTemplate>
                </asp:TemplateField>
                <asp:TemplateField>
                    <ItemTemplate>
                        <asp:ImageButton ImageUrl="~/Images/edit.png" runat="server" CommandName="Edit" ToolTip="Edit" Width="20px" Height="20px"/>
                        <asp:ImageButton ImageUrl="~/Images/delete.png" runat="server" CommandName="Delete" ToolTip="Delete" Width="20px" Height="20px"/>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:ImageButton ImageUrl="~/Images/save.png" runat="server" OnClientClick="return Validate(this);" CommandName="Update" ToolTip="Update" Width="20px" Height="20px"/>
                        <asp:ImageButton ImageUrl="~/Images/cancel.png" runat="server" CommandName="Cancel" ToolTip="Cancel" Width="20px" Height="20px"/>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:ImageButton ImageUrl="~/Images/addnew.png" runat="server" CommandName="AddNew" ToolTip="Add New" Width="20px" Height="20px"/>
                    </FooterTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>

我想在更新时验证电子邮件字段(它不应该为空)。

这是我尝试过的:-

function validate() 
{ 
 if(document.getElementById("<%=txtEmail.ClientID%>").value‌​=="")
 { 
 alert("Email Field can not be blank"); 
 document.getElementById("<%=txtEmail.ClientID%>").focus(‌​); 
 return false; 
 } 
 return true; 
 }

但是我收到错误消息，因为 txtEmail 在当前上下文中不存在。

我也用过这个方法:-

<script type="text/javascript">
    function Validate(lnkUpdate) {
     var txtEmail;
     var row = lnkUpdate.parentNode.parentNode;
     txtEmail = row.getElementsByID("txtEmail");

     if (txtEmail.value == null) {
         alert("Email Field can not be blank"); 
     }
     }

我在更新按钮上调用此方法但这也不起作用。我如何使用 javascript 做到这一点？我哪里做错了？

Answer 1

你可以给你的按钮添加一个类

<EditItemTemplate>
                        <asp:ImageButton ImageUrl="~/Images/save.png" runat="server" class="button_save" CommandName="Update" ToolTip="Update" Width="20px" Height="20px"/>
                        <asp:ImageButton ImageUrl="~/Images/cancel.png" runat="server" CommandName="Cancel" ToolTip="Cancel" Width="20px" Height="20px"/>
                    </EditItemTemplate>

然后在javascript中监听类的事件click

var buttonSave = document.getElementsByClassName("button_save");

for (var i = 0; i < buttonSave.length; i++) {
    buttonSave[i].addEventListener('click', Validate(buttonSave[i]), false);
}