Flex calls a method of custom class in webservice

public class ReturnResult
{
public int curIndex { get; set; }
public DataTable idxList { get; set; }
}
//Test the database connection
[WebMethod(Description = "!!! Test database connection, link string in")]
public bool conectDB()
{
strCon = ["sqlConDuke"];
conn = new SqlConnection(strCon);
try
{
();
return true;
}
catch (Exception)
{
return false;
}
finally
{
();
}
}

[WebMethod(Description = "Get detailed data based on <b>photo name</b> (DataTable), strTb,eg:PanView;strImgName,eg:20131019072740-0000150")]
public DataTable getInfoByImgName(string strTb, string strImgName)
{
bool ifCon = conectDB();
if (ifCon)
{
string sql_BfCar = "SELECT * FROM dbo." + strTb + " where ImageName LIKE '%" + strImgName + "%'";
da = new SqlDataAdapter(sql_BfCar, conn);
myds = new DataSet();
(myds);
return [0];
}
else
{
return null;
}
}


[WebMethod(Description = "Get all data of the Link based on <b>photo name</b> (ReturnResult), strTb,eg:PanView;strImgName,eg:20131019072740-0000150")]
public ReturnResult getLinkDTByImgName(string strTb, string strImgName)
{
ReturnResult returnResult = new ReturnResult();
bool ifCon = conectDB();
if (ifCon)
{
= Convert.ToInt32(getInfoByImgName(strTb, strImgName).Rows[0][0]);
string strLinkGuid = getInfoByImgName(strTb, strImgName).Rows[0][1].ToString();
string sql_BfCar = "SELECT * FROM dbo." + strTb + " where LinkGuid LIKE '%" + strLinkGuid + "%'";
da = new SqlDataAdapter(sql_BfCar, conn);
myds = new DataSet();
(myds);
= [0];
return returnResult;
}
else
{
return null;
}
}

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="/mxml/2009"
xmlns:s="library:///flex/spark"
xmlns:mx="library:///flex/mx" minWidth="955" minHeight="600" creationComplete="application1_creationCompleteHandler(event)">
<fx:Script>
<![CDATA[
import ;
import ;
import ;
import ;
import ;

public var arr:ArrayCollection=new ArrayCollection();
public var aaa:String=new String();

protected function webservice1_faultHandler(event:FaultEvent):void
{
(());
}
protected function getLinkDTByImgNameHandler(event:ResultEvent):void
{
// aaa=;
// arr=;

aaa=;
arr=;
(aaa+" "+());
}


protected function application1_creationCompleteHandler(event:FlexEvent):void
{
("PanView","20131019072740-0000150");
}

]]>
</fx:Script>
<fx:Declarations>
<!-- Put non-visual elements (such as services, value objects) here -->
<s:WebService wsdl="http://10.19.1.55/serverPano/?WSDL" fault="webservice1_faultHandler(event)">
<s:operation name="getLinkDTByImgName" result="getLinkDTByImgNameHandler(event)"></s:operation>
</s:WebService>
</fx:Declarations>
</s:Application>