Null Dereference C#

Question

11.3k views Asked by Marcus At 28 December 2016 at 02:26

if (ddl.SelectedValue != "")

After using Fortify to analyze my code, Fortify show me a vulnerability which is "Null Dereference".

How can i resolve this issue?

There are 2 answers

**Mitch Wheat** · Answer 1 · 2016-12-28 02:28:39

Mitch Wheat On 28 December 2016 at 02:28

Assuming ddl can never be null:

if (!String.IsNullOrEmpty(ddl.SelectedValue)
{

}

Otherwise:

if (ddl != null && !String.IsNullOrEmpty(ddl.SelectedValue)
{

}

**bbsimonbb** · Answer 2 · 2018-12-12 14:46:40

bbsimonbb On 12 December 2018 at 14:46

In C# 6 you have the null dereferencing operator, also called safe navigation operator, so you can do...

if (!String.IsNullOrEmpty(ddl?.SelectedValue)
{
    // ddl can be null and this will not throw.
}