Getting Non-Null Data

UPDATE: See my new post on this topic. (I also corrected code in this current post, where I changed to test for null before testing for DBNull.Value ... it was an oversight on my part. Sorry, hope it didn't cause anyone problems).

I see questions along these lines all the time:

//I'm doing this:
int CustID = (int)dsCustomer.Tables["Customer"].Rows[0]["CustID"];
// It throws an exception because CustID is DBNull in the data. 
// How do I handle this?

I have a CommonFunctions class that I use for things such as a GetNonNull( ) method (it's an old class, dating back to the 1.1 days, but it still works fine and so I have never updated it for 2.0, haven't really looked to see if it's even necessary).  This will work for any type of object, not just data in a DataSet, but is seems that DataSet access is  the commonly asked question.

This is implemented with many overloads, but here's an example of just a few:

public class CommonFunctions
{
    public static object GetNonNull(object Test, object Default)
    {
        if (Test != null && Test != DBNull.Value)
            return Test;
        else
            return Default;
    }
    public static string GetNonNull(object Test, string Default)
    {
        if (Test != null && Test != DBNull.Value) 
        {
            if(Test is DateTime) 
            {
                DateTime TestDT = Convert.ToDateTime(Test);
                DateTime SqlNull = new DateTime(1900, 1, 1);
            
                if(TestDT == SqlNull)
                    return Default;
            }
            else
            if (Test is bool)
            {
                bool YesNo = Convert.ToBoolean(Test);
                if (YesNo)
                    return "Yes";
                else
                    return "No";
            }
                    
            return Test.ToString().Trim();
        }
        else
            return Default;
    }
    public static int GetNonNull(object Test, int Default)
    {
        if (Test != null && Test != DBNull.Value)
            return Convert.ToInt32(Test);
        else
            return Default;
    }
    public static DateTime GetNonNull(object Test, DateTime Default)
    {
        
        if (Test != null && Test != DBNull.Value)
        {
            DateTime TestDT = Convert.ToDateTime(Test);
            DateTime SqlNull = new DateTime(1900, 1, 1);
            DateTime NetNull = new DateTime(1, 1, 1);
            
            if(TestDT != SqlNull && TestDT != NetNull)
                return TestDT;
            else
                return Default;
        }
        else
            return Default;
    }
}

These are just a sample of the overloads I use. I have a few more such as for bool, decimal, long and even a few differently named methods specifically for Dates, such as these next two:

public static string GetNonNullDate(object Test, string Default)
{
    if (Test != null && Test != DBNull.Value) 
    {
        if(Test is DateTime) 
        {
            DateTime TestDT = Convert.ToDateTime(Test);
            DateTime SqlNull = new DateTime(1900, 1, 1);
        
            if(TestDT != SqlNull)
                return TestDT.ToShortDateString();
        }
                
        return Default;
    }
    else
        return Default;
}
public static DateTime GetNonNullDate(object Test)
{
    if (Test != null && Test != DBNull.Value && Test is DateTime) 
        return Convert.ToDateTime(Test);
    else
        return new DateTime(1900, 1, 1);
}

Anyway, you get the point. Note that these are static methods, so no instantiation of the CommonFunctions class is necessary.To use them, you would simply have something like this:

int MyInt = CommonFunctions.GetNonNull(MyDataSet.Tables[0].Rows[0]["MyColumn"], 0);
// -or-
DateTime MyDatetime = CommonFunctions.GetNonNullDate(MyDataSet.Tables[0].Rows[0]["MyDateColumn"])