javascript - WebService C# (Ajax) 中缺少参数

Question

我正在尝试调用网络函数，但我不知道我是否犯了任何错误。 这是以下功能:

[WebMethod]
public string NumberOfHazardsToUser(string userid)
{
    JavaScriptSerializer json = new JavaScriptSerializer();
    command.CommandText = "select count(*) from Users_Hazards where User_ID = '" + userid + "'";
    command.Connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    if (reader.Read())
    {
        if ((int)reader.GetValue(0) != 0)
        {
            int count = (int)reader.GetValue(0);
            command.Connection.Close();
            return json.Serialize(count);
        }
    }
    command.Connection.Close();
    return json.Serialize(0);
}

我是这样调用它的

function getCountHazardsToUser() {
$.ajax({
    async: true,
    url: web + "/NumberOfHazardsToUser",
    method: "GET",
    data: '{"userid":"' + localStorage.getItem("id") + '"}',
    dataType: "json",
    contentType: "application/json",
    success: function (data) {
        var res = data.d;
        hazardsNumber = res;
    },
    error: function () {
        hazardsNumber = -1;
    }
});

这是回复 System.InvalidOperationException:缺少参数:userid。

Answer 1

我已经对您的代码进行了一次修改(更改 method:POST)并运行良好。

$.ajax({
    async: true,
    url: web + "/NumberOfHazardsToUser",
    method: "POST",
    data: '{"userid":"' + localStorage.getItem("id") + '"}',
    dataType: "json",
    contentType: "application/json",
    success: function (data) {
        var res = data.d;
        hazardsNumber = res;
    },
    error: function () {
        hazardsNumber = -1;
    }
});

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