javascript - asp.net 中的 500 内部服务器错误

Question

问题概述:我正在创建一个应用程序，其中有一个 html 选择列表，我可以从中选择一个类别，并使用 ajax webmethod 从该类别中获取项目和图像。

问题概述:我在 ajax linq to sql 中遇到了许多 500 错误并修复了它。但现在我正在开发 ado.net 应用程序，我面临的问题是当我从选择列表(catlist)中选择一个类别时，它从这里显示错误 error: function (xhr) {alert(xhr.status) );}.

  [ArgumentException]: Unknown web method elist.
 Parameter name: methodName
 at System.Web.Script.Services.WebServiceData.GetMethodData(String methodName)
 at System.Web.Handlers.ScriptModule.OnPostAcquireRequestState(Object sender, EventArgs eventArgs)
 at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
 at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
.

How can I fix this error. I thought I briefly describe my question.

Default.Aspx Code Overview:

Below is my HTML

<table>
    <tr>
        <td>
            <select id="catlist" runat="server" onchange="getImageUrl()"></select>
        </td>
        <td></td>
    </tr>
    <tr>
        <td>
            <img id="imgload" width="180" height="100" src="" alt="No Image Found" />
        </td>
        <td>
            <ul>
                <li>Description</li>
                <li>Loreum IspumLoreum IspumLoreum IspumLoreum IspumLoreum IspumLoreum IspumLoreum Ispum</li>
            </ul>
        </td>
    </tr>
</table>

下面是我的 Javascript 函数

function getImageUrl() {
        var catid = $("#catlist")[0].value;
        $.ajax({
            url: "Default.aspx/elist",
            data: { catId: catid },
            contentType: "Application/json; charset=utf-8",
            responseType: "json",
            method: "POST",
            success: function (response) {
                alert(response.d);
            },
            error: function (xhr) {
                alert(xhr.status);
            },
            Failure: function (response) {
                alert(response);
            }
        });
    }

Default.Aspx.cs 代码概述:

下面是我的自定义类

public class events
{
    public string EVE_NAME { get; set; }
    public string EVE_IMG_URL { get; set; }
    public string EVE_DESCRIPTION_SHORT { get; set; }
}

下面是Datatable方法

private static DataTable dt2(int catId)
{
    DataTable dataTable = new DataTable();
    SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=EVENT;Persist Security Info=True;User ID=sa;Password = 123");
        string query = "sp_view";

    SqlCommand cmd = new SqlCommand(query, conn);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.Add("@catID", SqlDbType.Int).Value = catId;
    conn.Open();
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    da.Fill(dataTable);
    return dataTable;
 }

下面是WebMethod

[WebMethod]
private static List<events> elist(int catId)
{
     List<events> eve = new List<events>();
     eve = (from DataRow row in dt2(catId).Rows
           select new events
           {
                   EVE_NAME = row["EVE_NAME"].ToString(),
                   EVE_IMG_URL = row["EVE_IMG_URL"].ToString(),
                   EVE_DESCRIPTION_SHORT = row["EVE_DESCRIPTION_SHORT"].ToString(),
           }).ToList();
     return eve;
 }

注意: 数据库列名称和事件类属性名称相同。

Answer 1

根据属性WebMethod的文档:

https://msdn.microsoft.com/en-us/library/byxd99hx(v=vs.90).aspx

Attaching the WebMethod attribute to a Public method indicates that you want the method exposed as part of the XML Web service. You can also use the properties of this attribute to further configure the behavior of the XML Web service method. For more information, see Code Model for XML Web Services in Managed Code.

我想乔恩·斯基特是对的。 :)