在使用WCF时，如何使用哪种数据结构返回使用FOR XML格式化的SQL Server查询结果？

Question

I'm using WCF to create a service that will query my SQL Server DB and return the response in a specific XML layout (shown here)

<SUP_LOCS>
    <SUP_LOC>
        <SUP_LOC_ID_DESC>Memphis TN</SUP_LOC_ID_DESC>
        <QTY_AVL>6</QTY_AVL>
        <ITEM_UOM>EA</ITEM_UOM>
    </SUP_LOC>
    <SUP_LOC>
        <SUP_LOC_ID_DESC>Los Angeles CA</SUP_LOC_ID_DESC>
        <QTY_AVL>1</QTY_AVL>
        <ITEM_UOM>EA</ITEM_UOM>
    </SUP_LOC>
</SUP_LOCS>

I am using FOR XML to make SQL Server produce the XML. This gives me the correct XML format I show above.

select location [Sup_LOC_ID_DESC] ...(shortened for brevity)... FOR XML raw('SUP_LOC'), root('SUP_LOCS'), elements

My question is what data structure should I use in my method? (shown here). In my example, I am using string but when I use the WCF test client, my response doesn't look like I thought it would (see image below)

public string GetInventory(string itemID)
{
    inventoryQuery = string.Format(inventoryQuery, itemID);
    string queryResult = _sub.Database.SqlQuery<string>(inventoryQuery).FirstOrDefault();
    return queryResult;
}

Answer 1

Your return type can be System.ServiceModel.Channels.Message and you can create a message using WebOperationContext.Current.CreateTextResponse method

So, your method can be like

public System.ServiceModel.Channels.Message GetInventory(string itemID)
{
    inventoryQuery = string.Format(inventoryQuery, itemID);
    string queryResult = _sub.Database.SqlQuery<string>(inventoryQuery).FirstOrDefault();
    return WebOperationContext.Current.CreateTextResponse(queryResult,"text/xml");
}