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How to pass null to int column in linq

How to assign null to int column in LINQ. eg.

 SQLDBDataContext sqlD = new SQLDBDataContext();
 var result = from p in sqlD.loadsRadius(Convert.ToInt32(Request["radius"]), .....

here, if Request ["radius"] is null, throws an error.

I could go through 0, but I need to change in many of the already existing routines.

Thanks in advance. Anil

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5 answers


You need to cast int to null, for example:



var result = from p in sqlD.loadsRadius(string.IsNullOrEmpty(Request["radius"]) ? (int?)null : int.Parse(Request["radius"]);
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If the exception is a FormatException, I assume that the value returned by Request ["radius"] is in fact the string "null". If Request ["radius"] actually returned null, Convert.ToInt32 () will return zero. You can try using with int.TryParse () to avoid the exception.



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as suggested by Codechef ..

int radius = -1;
int.TryParse(Request["radius"],out radius)
if(radius > 0) // you can remove this clause if you don't want this
{
SQLDBDataContext sqlD = new SQLDBDataContext();
 var result = from p in sqlD.loadsRadius(radius)
}
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Look at nullable types: Here.

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Can you use ?? operator :

Convert.ToInt32(Request["radius"] ?? "0")

If Request ["radius"] is null, it will return "0" instead.

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