从C＃中的WebMethod返回单个字符串值 [英] Return a single string value from a WebMethod in C#
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问题描述
我只想返回messageID，但是它不能正常工作。如何返回单个字符串值？
I want to return just messageID but it doesn't work correctly. How can I return a single string value?
[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;
}
推荐答案
我可以这样实现
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;
}
}
}
完整的实现是
<!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>
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