вызов функции ajax в javascript

Question

Я хочу вызвать Ajax в javascript, но он дает неопределенную ошибку CallPageMethod. Как его определить? и я новичок в Ajax. Вы можете мне помочь?

<script type="text/javascript">  
    function ValidateDelete() { 
     var result = CallPageMethod("IsLangExists", success, fail); 

     if (result == true) { 
      return confirm('Do you want to continue ?') 
     } 
     else alert('You can not delete this record'); 
    } 

    function success(response) { 
     //alert(response.d); 
    } 

    function fail(response) { 
     //alert("An error occurred."); 
    } 
</script> 
<asp:GridView ID="grdList" OnRowCommand="grdList_RowCommand"> 
    <Columns> 
     <asp:BoundField DataField="LangId" HeaderText="LangId" Visible="false" />    
     <asp:TemplateField HeaderText="Delete"> 
       <ItemTemplate> 
        <asp:ImageButton ID="imgBtnDelete" runat="server" CommandName="_Delete" CommandArgument='<%#Eval("LangId")%>' ImageUrl="~/Image/delete_icon.gif" OnClientClick="return ValidateDelete();" 
          ToolTip="Delete" /> 
       </ItemTemplate> 
     </asp:TemplateField> 
    </Columns>   
</asp:GridView> 

код за

[WebMethod] 
public static bool IsLangExists() 
{ 
    return true; 
} 

Answer 1

ли ваш CallPageMethod определен где-нибудь?

function CallPageMethod(methodName, onSuccess, onFail) { 
    var args = ''; 
    var l = arguments.length; 
    if (l > 3) { 
     for (var i = 3; i < l - 1; i += 2) { 
      if (args.length != 0) args += ','; 
      args += '"' + arguments[i] + '":"' + arguments[i + 1] + '"'; 
     } 
    } 
    var loc = window.location.href; 
    loc = (loc.substr(loc.length - 1, 1) == "/") ? loc + "default.aspx" : loc; 
    $.ajax({ 
     type: "POST", 
     url: loc + "/" + methodName, 
     data: "{" + args + "}", 
     contentType: "application/json; charset=utf-8", 
     dataType: "json", 
     success: onSuccess, 
     fail: onFail 
    }); 
} 

Чтобы получить возвращаемое значение вашего метода на стороне сервера, вам нужно будет использовать onSuccess обратного вызова, не проверив значение result:

function ValidateDelete() { 
    CallPageMethod("IsLangExists", success, fail); 
} 

function success(response) { 
    if (response.d) { 
     return confirm('Do you want to continue ?'); 
    } 

    alert('You can not delete this record'); 
} 


function fail(response) { 
    //alert("An error occurred."); 
} 

---

Вот как это должно все смотрят вместе:

<script type="text/javascript"> 

    function CallPageMethod(methodName, onSuccess, onFail) { 
     var args = ''; 
     var l = arguments.length; 
     if (l > 3) { 
      for (var i = 3; i < l - 1; i += 2) { 
       if (args.length != 0) args += ','; 
       args += '"' + arguments[i] + '":"' + arguments[i + 1] + '"'; 
      } 
     } 
     var loc = window.location.href; 
     loc = (loc.substr(loc.length - 1, 1) == "/") ? loc + "default.aspx" : loc; 
     $.ajax({ 
      type: "POST", 
      url: loc + "/" + methodName, 
      data: "{" + args + "}", 
      contentType: "application/json; charset=utf-8", 
      dataType: "json", 
      success: onSuccess, 
      fail: onFail 
     }); 
    } 

    function ValidateDelete() { 
     CallPageMethod("IsLangExists", success, fail); 
    } 

    function success(response) { 
     if (response.d) { 
      return confirm('Do you want to continue ?'); 
     } 

     alert('You can not delete this record'); 
    } 

    function fail(response) { 
     //alert("An error occurred."); 
    } 

</script> 
<asp:GridView ID="grdList" OnRowCommand="grdList_RowCommand"> 
    <Columns> 
     <asp:BoundField DataField="LangId" HeaderText="LangId" Visible="false" />    
     <asp:TemplateField HeaderText="Delete"> 
       <ItemTemplate> 
        <asp:ImageButton ID="imgBtnDelete" runat="server" CommandName="_Delete" CommandArgument='<%#Eval("LangId")%>' 
          ImageUrl="~/Image/delete_icon.gif" OnClientClick="return ValidateDelete();" 
          ToolTip="Delete" /> 
       </ItemTemplate> 
     </asp:TemplateField> 
    </Columns>   
</asp:GridView>