Question

我有一个Jquery ajax函数，可以调用c＃方法。即使它应该返回的字符串是Json格式，该函数也总是返回null。如何在Jquery函数中获取返回值？

function GetScores() {
$.ajax({
    type: 'POST',
    url: 'Default.aspx/GetTopScores',
    contentType: 'application/json; charset=utf-8',
    dataType: 'json',
    success: function (data, textStatus, jqXHR) {
        alert(data.d); // Always NULL
    },
    error: function (jqXHR, textStatus, errorThrown)
    {
        alert('ERROR!!');
    }
});

}

    public static string GetTopScores()
    {
        string result = string.Empty;
        DataTable dt = new DataTable();
        try
        {
            using (SqlConnection conn = new SqlConnection())
            {
                conn.ConnectionString = "Data Source=*****;Initial Catalog=beachlings;Persist Security Info=True;User ID=******;Password=******;MultipleActiveResultSets=True;Application Name=EntityFramework";
                conn.Open();

                string query = "Select TOP 20 PlayerName, SiteName, Score from HighScores ORDER BY SCORE DESC";

                SqlCommand cmd = new SqlCommand(query, conn);

                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(dt);


                List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>();
                Dictionary<string, object> row;
                foreach (DataRow dr in dt.Rows)
                {
                    row = new Dictionary<string, object>();
                    foreach (DataColumn col in dt.Columns)
                    {
                        row.Add(col.ColumnName, dr[col]);
                    }
                    rows.Add(row);
                }

                 string s =  JsonConvert.SerializeObject(rows);

                return s;
            }
        }
        catch (Exception ex)
        {
            return null;
        }
    }

Answer 1

终于找到导致javascript返回null的原因。我从另一个方法中调用GetTopScores（）而不是返回字符串我返回void。谢谢你的帮助:)

Jquery Ajax函数始终返回null

1 个答案: