Chris Chris - 3 months ago 14
C# Question

How do I check for null or empty string for many arguments? - C#

I have the below method, which I need to check for whether the arguments are empty or null.

public DB Where(string field, string operat, string value, string andOr, string field2, string operat2, string value2)
{
_Where = " WHERE " + field + " " + operat + " @" + field + "1 " + andOr + " " + field2 + " " + operat2 + " @" + field2 + "2 ";
_Params.Add(field + "1", value);
_Params.Add(field2 + "2", value2);
return this;
}


I have found the string.IsNullOrWhiteSpace method however this would require this much code:

if (string.IsNullOrWhiteSpace(field))
throw new ArgumentException("field Cannot be null or be empty");

if (string.IsNullOrWhiteSpace(operat))
throw new ArgumentException("operat Cannot be null or be empty");

if (string.IsNullOrWhiteSpace(value))
throw new ArgumentException("value Cannot be null or be empty");

if (string.IsNullOrWhiteSpace(andOr))
throw new ArgumentException("andOr Cannot be null or be empty");

if (string.IsNullOrWhiteSpace(field2))
throw new ArgumentException("field2 Cannot be null or be empty");

if (string.IsNullOrWhiteSpace(operat2))
throw new ArgumentException("operat2 Cannot be null or be empty");

if (string.IsNullOrWhiteSpace(value2))
throw new ArgumentException("value2 Cannot be null or be empty");


Is there any way of shortening this?

Also, I have tried creating a custom method for this task, however it throws an exception in the custom method instead of the Where() method which makes it tricky to debug.

Ian Ian
Answer

You could check the value one by one or creating intermediate function to do that.

Alternatively, my suggestion is: you could put all the inputs in an array and use LINQ Any to check all of them at once:

public DB Where(string field, string operat, string value, string andOr, string field2, string operat2, string value2)
{
    string[] inputs = {field, operat, value, andOr, field2, operat2, value2}
    if (inputs.Any(x => string.IsNullOrWhiteSpace(x))){
        //throw exception
    }
    //continue with your method, all inputs are OK
}
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