代码之家 › 专栏 › 技术社区 › Mike Webb

如何使用jQuery获取Ajax请求数据?

response ajax jquery javascript

Mike Webb · 技术社区 · 16 年前

我有一个Ajax请求:

$.ajax({ url: "MyPage.aspx", 
    data: params,
    success: function(data) {
        // Check results                
        $('#testp').append(data.message);
        enableForm();
    },
    error: function() {
        alert('Unable to load the permissions for this user level.\n\nYour login may have expired.');
        enableForm();
    },
    dataType: "json"
});

在请求页面上,有一个C#代码在加载页面的末尾执行此操作:

Response.AppendHeader("X-JSON", result);

{ "success": true, "message": "SUCCESS", "user_level": 25, "switches": [ { "number": 30, "is_enabled": false, "is_default": false }, { "number": 30, "is_enabled": false, "is_default": false } ]}

请求成功返回,但“data”为空。我错过了什么?

3 回复 | 直到 16 年前

Dave Ward 16 年前

您的主要问题似乎是在HTTP报头中返回JSON数据,而不是作为响应的内容。你可能想这样做:

Response.ContentType = "application/json";
Response.Write(result);
Response.End();

public class PermissionsResult
{
  public bool success;
  public string message;
  public int user_level;

  public List<Switch> switches;
}

public class Switch
{
  public int number;
  public bool is_enabled;
  public bool is_default;
}

// The combination of a WebMethod attribute and public-static declaration
//  causes the framework to create a lightweight endpoint for this method that
//  exists outside of the normal Page lifecycle for the ASPX page.
[WebMethod]
public static PermissionsResult GetPermissions(int UserLevel)
{
  PermissionsResult result = new PermissionsResult();

  // Your current business logic to populate this permissions data.
  result = YourBusinessLogic.GetPermissionsByLevel(UserLevel);

  // The framework will automatically JSON serialize this for you.
  return result;
}

您必须将其与自己的服务器端数据结构相适应,但希望您能理解。如果已经有可用所需数据填充的现有类,则可以使用这些类,而不是为传输创建新类。

call an ASP.NET AJAX Page Method with jQuery

$.ajax({
  // These first two parameters are required by the framework.
  type: 'POST',
  contentType: 'application/json',
  // This is less important. It tells jQuery how to interpret the
  //  response. Later versions of jQuery usually detect this anyway.
  dataType: 'json',
  url: 'MyPage.aspx/GetPermissions',
  // The data parameter needs to be a JSON string. In older browsers,
  //  use json2.js to add JSON.stringify() to them.
  data: JSON.stringify({ UserLevel: 1}),
  // Alternatively, you could build the string by hand. It's messy and
  //  error-prone though:
  data: "{'UserLevel':" + $('#UserLevel').val() + "}",
  success: function(data) {
    // The result comes back wrapped in a top-level .d object, 
    //  for security reasons (see below for link).
    $('#testp').append(data.d.message);
  }
});

关于数据参数,以下是需要字符串的信息: http://encosia.com/2010/05/31/asmx-scriptservice-mistake-invalid-json-primitive/

此外,这里还有更多关于使用JSON.stringify文件()方法: http://encosia.com/2009/04/07/using-complex-types-to-make-calling-services-less-complex/

.d问题一开始可能令人困惑。基本上,JSON会像这样返回,而不是像您预期的那样:

{"d": { "success": true, "message": "SUCCESS", "user_level": 25, "switches": [ { "number": 30, "is_enabled": false, "is_default": false }, { "number": 30, "is_enabled": false, "is_default": false } ]}}

http://encosia.com/2009/02/10/a-breaking-change-between-versions-of-aspnet-ajax/

Silkster 16 年前

答案应该是:

在ajax设置的url值末尾添加方法名:

确保使用该方法指向正确的页面,并确保该方法具有WebMethod()属性。

$。ajax几乎可以为您处理所有事情。如果AJAX调用成功,返回数据将作为参数传递给success函数,即:

success: function (data) { 
    //do something 
}

“的值”数据.消息仅当“message”是返回数据的属性时,才可用。在您的例子中,id为“testp”的元素应该接收数据.消息,但对象的其余部分未被使用。

非常棒的博客,您可以查看AJAX for.Net的所有内容: http://encosia.com/

http://www.json.org/js.html )测试返回的数据。只需添加

alert(JSON.stringify(data));

Community Mohan Dere 9 年前

Can't get jQuery Ajax to parse JSON webservice result