Replacing empty string/null value with 0 prior to assigning value to a property

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Got the following code to assign a value which is defined in the app.config and Cache, this value is retrieved in cache as "public enum class" such as in the following:

C#

public static class Cache
{
  public enum jobDetails { x }; 
}

Here is the variable defined in app.config:

C#

<add key="x" value=""/>

and the objectDetails is defined as in the following:

C#

public class objectDetails
{ 
   public int x { get; set; }
}

Here is the piece of code that I am having trouble with:

C#

objectDetails.x = Convert.ToInt16(jobDetails.GetValues(Cache.jobDetails.x.ToString().Trim())[0]);

My question is here is if "x" is defined as null value ("") in the app.config file then the above code would fail (due to string format error), so how can I check the value upfront if it is a null value ("") then assign a 0 to it before assigning the value to objectDetails.x (and do that elegantly).

Posted 21-Sep-12 8:20am

Member 8714829

Updated 21-Sep-12 8:23am

v2

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[no name] 21-Sep-12 14:23pm

String.IsNullOrWhiteSpace

2 solutions

Solution 1

VB

if (jobDetails.X.HasValue)
...{ assign to objectDetails}

Posted 21-Sep-12 8:33am

ShotDriller

v2

Comments

fjdiewornncalwe 21-Sep-12 14:35pm

My vote of 1: It's not a nullable type.

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fjdiewornncalwe · Accepted Answer · 2012-09-21T08:34:00

Solution 2

The error you are receiving is because Convert.ToInt16 will throw an exception if the argument cannot be parsed into a 16bit integer, so you have to ensure that if you make a call to Convert.ToInt16 the argument you supply it is valid.

In your case the problem in Cache.jobDetails.X.ToString() being empty or null, so string.IsNullOrEmpty(Cache.jobDetails.x.ToString()) is what you need to check.

eg.

C#

objectDetails.x = 
   string.IsNullOrEmpty(Cache.jobDetails.x.ToString().Trim()) 
      ? 0 
      : Convert.ToInt16(jobDetails.GetValues(Cache.jobDetails.x.ToString().Trim())[0]);

Posted 21-Sep-12 8:34am

fjdiewornncalwe

Updated 21-Sep-12 8:53am

v3

Comments

Member 8714829 21-Sep-12 14:47pm

This looks like something I can use and re use through out my code to update all properties like this one. One comment to mention, I made it work by changing your solution as in the following:
objectDetails.x =
string.IsNullOrEmpty(Convert.ToInt16(jobDetails.GetValues(Cache.jobDetails.x.ToString().Trim())[0]) ? 0 : Convert.ToInt16(jobDetails.GetValues(Cache.jobDetails.x.ToString().Trim())[0]);

thank you!

fjdiewornncalwe 21-Sep-12 14:51pm

Your change won't work. The change you made effectively makes the statement act EXACTLY as your original problem statement. The issue is that Convert.ToInt16 will throw the exception if Cache.JobDetails.x.ToString() is empty or null, so doing a string.IsNullOrEmpty on the Convert statement will still result in an exception. Use the code the way I gave it to you because yours won't work.

Member 8714829 24-Sep-12 13:52pm

Thank you for the note, I've detected this issue last week during my testing and made the correction, again many thanks for your follow up!!