null string concatenation

[MiddleTommy]

When building expressions in the designer and there is a null string the resulting string is null

type = null
size = "5x5x1/2"
length = "5 feet"

expression
=Fields.type + " " + Fields.size + " " + Fields.grade

resulting value is null in report textbox

It sure would be nice to Directly support string.Format(string, params object[] items) in expressions.
My guess is the params is not easily translated. from an expression.

[Steve]

Hello MiddleTommy,

You can handle null values with the built-in IsNull Function. Generally formatting any string can be easily achieves with Member Access i.e. ToString('your_format'). Another approach is creating User Functions where you can format the field value using String.Format

Kind regards,
Steve
the Telerik team

[MiddleTommy]

I got the work around OK
I wrote a user function to handle the string formatting. But I had to specify the exact amount of arguments (no biggie really)
However my point was

string str1 = null;
string str2 = "Hi Mom";

In Telerik.Reports.Expression
str1 + str2 = null

In C#
str1 + str2 = "Hi Mom"

It is very tedious to check IsNull on every string in a report to assure proper output.

[Steve]

Hi MiddleTommy,

This behavior is by design and behaves similarly to concatenation in SQL. NULL is an unknown
value and the result would also be unknown value.

Greetings,
Steve
the Telerik team