LINQ Replace DBNull with Blank String

Question

In this example, an error is raised if either row.FirstName or row.LastName are NULL.

How do I rewrite the Select clause, to convert a DBNull value to a blank string ""?

Dim query = From row As myDataSet.myDataRow in myDataSet.Tables("MyData") _
            Select row.FirstName, row.LastName

NOTE: Since the DataSet is strongly-typed. I can use row.isFirstNameNull(), but IIF(row.isFirstNameNull(), "", row.FirstName) will not work since all parameters are referenced.

Simon Fox · Accepted Answer · 2010-03-10 21:07:24Z

5

In your note you have mentioned IIf(row.isFirstNameNull(), "", row.FirstName) replace that with If(row.isFirstNameNull(), "", row.FirstName) which will not evaluate the false part if the condition is true

answered Mar 10, 2010 at 21:07

Simon Fox

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Patrick Karcher · Accepted Answer · 2010-03-10 21:08:56Z

1

Use VB's ternary operator "if" :

Dim query = From row As myDataSet.myDataRow in myDataSet.Tables("MyData") _
    Select if(row.isFirstNameNull(), "", _
        row.FirstName), if(row.isLastNameNull(), "", row.LastName)

answered Mar 10, 2010 at 21:08

Patrick Karcher

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Pontus Gagge · Accepted Answer · 2010-03-10 21:11:22Z

-1

what about row.FirstName ?? string.Empty

edited Mar 10, 2010 at 21:11

Pontus Gagge

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answered Mar 10, 2010 at 21:07

UshaP

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1 Comment

Mark Brackett Over a year ago

Works great for C# - not so much for VB.NET. VB.NET folks should use the If operator's coalesce form[1]: If(row.FirstName, string.Empty). Of course, that doesn't work for this example either - since DbNull.Value IsNot Nothing[2]. [1] msdn.microsoft.com/en-us/library/bb513985.aspx [2] codebetter.com/blogs/peter.van.ooijen/archive/2004/04/12/…

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