arcgis server回调

老是搞忘怎么写，简单的做一下备忘

      public string m_Callback = "";
    public string sCallBackFunctionInvocation = "";

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            Session["SourceLayer"] = "";
        }
        DropDownList1.Attributes.Add("onchange", "ChangeDDLContext()");
        m_Callback = Page.ClientScript.GetCallbackEventReference(Page, "argument", "processCallbackResult", "context", "processCallbackError", true);
        sCallBackFunctionInvocation = Page.ClientScript.GetCallbackEventReference(this, "message", "HandleResponse", "context", "postBackError", true);
       
    }

    protected void Page_PreRender(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            ESRI.ArcGIS.ADF.Web.DataSources.IMapFunctionality mf = (ESRI.ArcGIS.ADF.Web.DataSources.IMapFunctionality)Map1.GetFunctionality(1);
            ESRI.ArcGIS.ADF.Web.DataSources.IGISResource gisresource = mf.Resource;
            bool supported = gisresource.SupportsFunctionality(typeof(ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality));
            if (supported)
            {
                ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality qfunc=(ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality)gisresource.CreateFunctionality(typeof(ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality), null);
                string[] libs;
                string[] lnames;
                qfunc.GetQueryableLayers(null, out libs, out lnames);
                for (int i = 0; i < lnames.Length; i++)
                {
                    DropDownList1.Items.Add(lnames[i]);
                }
                Session["SourceLayer"] = DropDownList1.Items[0].Value;
            }
        }
    }

    #region ICallbackEventHandler成员
    private string _callbackArg;
    string ICallbackEventHandler.GetCallbackResult()
    {
        return RaiseCallbackeEvent(_callbackArg);
    }
    void ICallbackEventHandler.RaiseCallbackEvent(string eventArgument)
    {
        _callbackArg = eventArgument;
    }
    #endregion
    private string RaiseCallbackeEvent(String _callbackArg)
    {
        string v = "";
        if (_callbackArg.Contains("ddl"))
        {
            ChangeDropDownListServer(_callbackArg);
        }
        else if (_callbackArg.Contains("Map"))
        {

            //try
            //{
                //请求字符串
                NameValueCollection keyValColl = CallbackUtility.ParseStringIntoNameValueCollection(_callbackArg);
                if (keyValColl["Type"].ToString() == "findPath")
                {
                    System.Text.StringBuilder sb = new System.Text.StringBuilder();
                    //起点名称
                    string Input1 = keyValColl["p1"];
                    //终点名称
                    string Input2 = keyValColl["p2"];
                    //路径分析
                    //无障碍点分析类调用
                    //findpath findpath = new findpath();
                    //findpath.doFindPath(Input1, Input2, Map1);
                    ////有障碍点分析类调用
                    //findBarrierPath findpath = new findBarrierPath();
                    //findpath.doFindPath(Input1, Input2, Map1);
                    //有多个障碍点分析类调用
                    findBarrierPath2 findpath = new findBarrierPath2();
                    findpath.doFindPath(Input1, Input2, Map1);
                    //直接调用
                  //  doFindPath(Input1, Input2);
                }
        }
            // innercontent相当于innerhtml
         //   CallbackResult cr = new CallbackResult("div", "griddiv", "innercontent", returnstring);

            //CallbackResult crl = new CallbackResult("Gradview1", null, "innercontent", null);
            //Map1.CallbackResults.Add(crl);
            v = Map1.CallbackResults.ToString();
          
            return v;

  <script type="text/javascript" language="javascript">
         
         var context;
        
         function ChangeDDLContext()
         {
            context = 'DDLContext';
            ChangeClient();
         }
     function ChangeClient()
     {
        var message;
           
        if (context == 'DDLContext'){
             var ddl1value = document.getElementById('DropDownList1').value;
         
           
             message = 'ddl';
             message += ',' + ddl1value;
        }
           
       if (context == 'BufferTextBox'){
           var bufboxvalue = document.getElementById('TextBox1').value;
               
           message = 'bufbox';
           message += ',' + bufboxvalue;
           
      }
           
       <%=sCallBackFunctionInvocation%>
     }
     function search()
     {
        //起点的名称
        var v1=document.getElementById("txtBegin").value;
        //终点的名称
        var v2=document.getElementById("txtEnd").value;
        var argument = "ControlID=Map1&ControlType=Map&Type=findPath&p1="+v1+"&p2="+v2;
        var context = "Map";
        var rv=<%= m_Callback %>;
      
        eval(rv);

    }
    function searchClosestFacility()
    {
        //设施的名称
        var v1=document.getElementById("txtFacility1").value;
        var v2=document.getElementById("txtFacility2").value;
        //事件的名称
        var v3=document.getElementById("txtIncident").value;
        var argument="ControlID=Map1&ControlType=Map&Type=ClosestFacility&p1='"+v1+"'&p2='"+v2+"'&p3="+v3;
        var context="Map";
        var rv=<%=m_Callback %>;
        eval(rv);
    }
    function processCallbackError()
    {
      alert(66);
    }
    function HandleResponse()
    {
    }
  
    </script>

  <script type="text/javascript" language="javascript">
         
         var context;
        
         function ChangeDDLContext()
         {
            context = 'DDLContext';
            ChangeClient();
         }
     function ChangeClient()
     {
        var message;
           
        if (context == 'DDLContext'){
             var ddl1value = document.getElementById('DropDownList1').value;
         
           
             message = 'ddl';
             message += ',' + ddl1value;
        }
           
       if (context == 'BufferTextBox'){
           var bufboxvalue = document.getElementById('TextBox1').value;
               
           message = 'bufbox';
           message += ',' + bufboxvalue;
           
      }
           
       <%=sCallBackFunctionInvocation%>
     }
     function search()
     {
        //起点的名称
        var v1=document.getElementById("txtBegin").value;
        //终点的名称
        var v2=document.getElementById("txtEnd").value;
        var argument = "ControlID=Map1&ControlType=Map&Type=findPath&p1="+v1+"&p2="+v2;
        var context = "Map";
        var rv=<%= m_Callback %>;
      
        eval(rv);

    }
    function searchClosestFacility()
    {
        //设施的名称
        var v1=document.getElementById("txtFacility1").value;
        var v2=document.getElementById("txtFacility2").value;
        //事件的名称
        var v3=document.getElementById("txtIncident").value;
        var argument="ControlID=Map1&ControlType=Map&Type=ClosestFacility&p1='"+v1+"'&p2='"+v2+"'&p3="+v3;
        var context="Map";
        var rv=<%=m_Callback %>;
        eval(rv);
    }
    function processCallbackError()
    {
      alert(66);
    }
    function HandleResponse()
    {
    }
  
    </script>