Question

我想只返回messageID但它无法正常工作。如何返回单个字符串值？

    [WebMethod]
    public string messageComeGetID(string from, string to)
    {
        try
        {
            sqlConn.Open();
        }
        catch (Exception e)
        {
            return null;
        }
        // select messageID from tblMessage where [from] = '2' AND [to] = '4' gibi.
        SqlCommand cmd3 = new SqlCommand("select messageID from tblMessage where [from]=@from AND [to]=@to", sqlConn);

        cmd3.Parameters.AddWithValue("@from", from);
        cmd3.Parameters.AddWithValue("@to", to);

        cmd3.Connection = sqlConn;
        object value = cmd3.ExecuteScalar();
        string messageID = Convert.ToString(value);
        cmd3.ExecuteNonQuery();
        cmd3.Dispose();
        sqlConn.Close(); 

        return messageID;
    }

Answer 1

我可以像这样实施的 WebService1.asmx

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Script.Serialization; using System.Web.Script.Services; using System.Web.Services; namespace StackOverflow_Solve.Services { /// <summary> /// Summary description for WebService1 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. [System.Web.Script.Services.ScriptService] public class WebService1 : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World"; } [WebMethod] [ScriptMethod(ResponseFormat = ResponseFormat.Json)] public string GetMessage() // Home.CS { //return "GOGO"; Context.Response.Output.Write("Hello World"); Context.Response.End(); return string.Empty; } } }

完全实施

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> <script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script> </head> <body> <head> //HTML and Ajax <title></title> <script> function GetMessage() { //Load jQuery($) to Use $(function() { $.get("WebService1.asmx/GetMessage", function (data) { console.log(data); $("p").html(data); }); }); } </script> </head> <body> <input type="button" onclick="GetMessage()" value="Get Message" /> <p></p> </body> </body> </html>

从C＃中的WebMethod返回单个字符串值

1 个答案: