如何使用Linq在C＃中创建if else语句

Question

I'm creating a web api with linq to sql. I need to add an if statement in my. I cant find anything online It seem like everyone is using entityframework.

public List<customerorderhistory> GetCustomerOrderHistory(string customerID)
{
    try 
    {
        List<customerorderhistory> results = new List<customerorderhistory>();
        NorthwindDataContext dc = new NorthwindDataContext();
        foreach (CustOrderHistResult oneOrder in dc.CustOrderHist(customerID))
        {
            results.Add(new CustomerOrderHistory()
            {
                ProductName = oneOrder.ProductName,
                Total = oneOrder.Total ?? 0
            });
        }
        return results;
    }
    catch (Exception ex)
    {
        //  Return any exception messages back to the Response header
        OutgoingWebResponseContext response = WebOperationContext.Current.OutgoingResponse;
        response.StatusCode = System.Net.HttpStatusCode.InternalServerError;
        response.StatusDescription = ex.Message.Replace("\r\n", "");
        return null;
    }
}

He is what I have tried. I think I may be putting the if statement in the wrong place. Any help would be appreciated.

public List<customerorderhistory> GetCustomerOrderHistory(string customerID)
{
    try 
    {
        List<customerorderhistory> results = new List<customerorderhistory>();
        NorthwindDataContext dc = new NorthwindDataContext();
        foreach (CustOrderHistResult oneOrder in dc.CustOrderHist(customerID))
        {
            results.Add(new CustomerOrderHistory()
            {
                if (oneOrder.RecordID == 'A')
                {
                    ProductName = "Archived Product"
                }
                else
                {
                ProductName = oneOrder.ProductName,
                }
                Total = oneOrder.Total ?? 0
            });
        }
        return results;
    }
    catch (Exception ex)
    {
        //  Return any exception messages back to the Response header
        OutgoingWebResponseContext response = WebOperationContext.Current.OutgoingResponse;
        response.StatusCode = System.Net.HttpStatusCode.InternalServerError;
        response.StatusDescription = ex.Message.Replace("\r\n", "");
        return null;
    }
}

Answer 1

Assuming you want to mask the product name if oneOrder.ProductID == 'A' ...

results.Add(new CustomerOrderHistory
{
    /*...*/,
    ProductName = (oneOrder.RecordID == 'A' ? "Archived Product" : oneOrder.ProductName),
    /*... */
});

Can place the condition when you assign using conditional operator .

Optionally, you could store it in a variable before instantiating your object:

var productName = oneOrder.ProductName;
if (oneOrder.ProductID == 'A')
{
    productName = "Archived Product";
}
results.Add(new CustomerOrderHistory
{
    /*...*/,
    ProductName = productName,
    /*... */
});