CODEWITHSUNDEEP
c#stringstringbuilderisnullorempty
Andrew Day
Andrew Day

Reputation: 607

Can I use .ToString().IsNullOrEmpty() on a StringBuilder object

 /*Class definition*/
public class ConcreteClassModel : BaseModel
{
...
public bool IntersectsWith(ConcreteClassModel ccm)
    {
        ccm.StartDateDT = DateTime.Parse(ccm.StartDate);
        ccm.EndDateDT = DateTime.Parse(ccm.EndDate);
        this.StartDateDT = DateTime.Parse(this.StartDate);
        this.EndDateDT = DateTime.Parse(this.EndDate);

        return !(this.StartDateDT > ccm.EndDateDT || this.EndDateDT < ccm.StartDateDT);
    }
}
/*Inside Controller Method*/
List<ConcreteClassModel> periods = LoadAllByParameters<ConcreteClassModel>(
            ccm.CoverId, x => x.CoverId,
            ccm.SectionId, x => x.SectionId);
var intersectingPeriods =
            periods.Where(x => x.IntersectsWith(ccm));
StringBuilder partReply = intersectingPeriods.Aggregate(new StringBuilder(), (a, b) => a.Append(b));

********if (!partReply.ToString().IsNullOrEmpty())***************************
        {
            string reply =
                "<div id='duplicateErrorDialog' title='Duplication Error'><span> Duplicate Period(s)</br>" +
                partReply + "</span></ div >";

            return Json(reply, JsonRequestBehavior.AllowGet);
        }    
return Json(null, JsonRequestBehavior.AllowGet);

The above seems to work fine and if no duplicate date periods are found the null responce will trigger my javascript to save. However is it ok to use: if (!partReply.ToString().IsNullOrEmpty()) As StringBuilder does not have its own .IsNullOrEmpty() equivalent? Every comment, question etc that I can find relates to Strings only, and cant see anything on MSDN!

Upvotes: 0

Views: 3884

Answers (2)

Drew Kennedy
Drew Kennedy

Reputation: 4168

You could create a quick method to help check if your StringBuilder object is null or empty:

private bool IsStringBuilderNullOrEmpty(StringBuilder sb) {
    return sb == null || sb.Length == 0);
}

//text examples

StringBuilder test = null;
Console.WriteLine(IsStringBuilderNullOrEmpty(test));//true


StringBuilder test = new StringBuilder();
test.Append("");

Console.WriteLine(IsStringBuilderNullOrEmpty(test));//true

StringBuilder test = new StringBuilder();
test.Append("hello there");

Console.WriteLine(IsStringBuilderNullOrEmpty(test));//false

Upvotes: 0

Jacob Krall
Jacob Krall

Reputation: 28825

In your case, partReply can never be null or empty, because Enumerable.Aggregate throws an InvalidOperationException when there are no input elements. Your code is crashing.

In general cases, you can compare the Length property with 0, e.g.:

if (partReply.Length > 0)

Upvotes: 2

Related Questions