How to check for a specific value in List<T> foreach loop

Hello Experts,

Need help checking for a specific value in List<T> foreach loop. If there is specific value then display a specific string value.

For example, how do I…

If (value.something_2 == “Null”)
{
    value.something_2 == “.“;
}
Elseif (value.something_2 == “ “)
{
    value.something_2 == “0”;
}

Open in new window



How would I incorporate the "If" statement within the “foreach” loop?

See code

protected void MyReport(string filename, IMyRepository repository)
        {

            using (FileStream fileStream = new FileStream(Server.MapPath(@"~/Includes/") + filename, FileMode.Create))

            {

                using (StreamWriter writer = new StreamWriter(fileStream))
                {

                    List<Report> _report = repository.GetMyReport().ToList();

                    foreach (var value in _report)
                    {


String row01 = String.Format("{0, -10}{1, 23}{2, 120}{3, 8}", value.somthing_1, values.something_2, value.something_3);

String row02 = String.Format("{0, -10}{1, 23}{2, 120}{3, 8}", value.somthing_4, values.something_5, value.something_6);



Writer.WriteLine(row01);
Writer.WriteLine(row02);


    }


   }
      writer.Close();
}
}

Open in new window


When I write the "if" statment within the foreach loop I get an error...
"only assignment expression can be used as statement".
and I get other errors if I re-write the "If" statement.

Thank you for your help.
iNetBlazerAsked:
Who is Participating?
 
AndyAinscowConnect With a Mentor Freelance programmer / ConsultantCommented:
OK, that seems to be the value can never be " ", which makes it fractionally simpler code:

string s2;
if (value.something_2 == “Null”)
{
    s2 == “.“;
}
else
  s2 = value.something_2.ToString();
0
 
AndyAinscowFreelance programmer / ConsultantCommented:
Does this do what you want?

                    foreach (var value in _report)
                    {


Writer.WriteLine(String.Format("{0, -10}{1, 23}{2, 120}{3, 8}", value.somthing_1, values.something_2, value.something_3));
Writer.WriteLine(String.Format("{0, -10}{1, 23}{2, 120}{3, 8}", value.somthing_4, values.something_5, value.something_6));


    }
0
 
AndyAinscowFreelance programmer / ConsultantCommented:
Sorry, ignore that previous comment.  I misunderstood what you wanted.

instead of:
 
foreach (var value in _report)
                    {

Open in new window

you would be better to loop through this way (because the compiler doesn't like the object in the foreach being modified whilst in the foreach loop):
for(int i = 0; i < _report.Length; i++)
{
  var value = _report[i];

Open in new window

If the 'T' is a reference type changing the value inside the object will change the value in the original object.  Is that what you wanted?  If not then you need to extract the individual contents into local strings and modify those.
0
The new generation of project management tools

With monday.com’s project management tool, you can see what everyone on your team is working in a single glance. Its intuitive dashboards are customizable, so you can create systems that work for you.

 
iNetBlazerAuthor Commented:
Ok, Keeping in mind that the values are of type decimal and is returned by SQL Db via EntityFramework.  There are values within the Db that have "Null" and/or Whitespace.  I need the check for this and if the value have "Null" then display "." is the value has Whitespace then display "0".
0
 
AndyAinscowFreelance programmer / ConsultantCommented:
string s2;
if (value.something_2 == “Null”)
{
    s2 == “.“;
}
else if (value.something_2 == “ “)
{
    s2 == “0”;
}
else
  s2 = value.something_2.ToString();
0
 
iNetBlazerAuthor Commented:
Get error...

Operator '==' cannot be applied to operands of type 'decimal?' and 'string'
0
 
Salim FayadCommented:
You should use Report instead of var in your foreach loop. So, instead of:
foreach (var value in _report)

Open in new window


You should write it:
foreach (Report value in _report)

Open in new window

0
 
AndyAinscowFreelance programmer / ConsultantCommented:
@The_eagle, why should that have an effect?  There is no difference in those two foreach statements.


Excerpt from:  http://msdn.microsoft.com/en-us/library/bb383973.aspx

Beginning in Visual C# 3.0, variables that are declared at method scope can have an implicit type var. An implicitly typed local variable is strongly typed just as if you had declared the type yourself, but the compiler determines the type. The following two declarations of i are functionally equivalent:

var i = 10; // implicitly typed
int i = 10; //explicitly typed
0
 
Salim FayadConnect With a Mentor Commented:
By the way, there is another bug, you cannot assign with the "==", you should use one equal:
if (value.something_2 == “Null”)
{
    s2 == “.“;
}
else if (value.something_2 == “ “)
{
    s2 == “0”;
}
else
  s2 = value.something_2.ToString(); 

Open in new window


should be:
if (value.something_2 == “Null”)
{
    s2 = “.“;
}
else if (value.something_2 == “ “)
{
    s2 = “0”;
}
else
  s2 = value.something_2.ToString(); 

Open in new window

0
 
iNetBlazerAuthor Commented:
@Guru and @Ace,

You both pointed me in the right direction structuring the "If" statement.  Refer to the below code as the solution resulting from both your suggestions.

In referencing the code keep in mind the Db has a column of type decimal and it can have a value or Null.

foreach (var value in report)
{
  string dot = ".";
  string reportValue;

if (!value.someDecimalValue)
{
  reportValue = dot;
}
else
{
  reportValue = value.someDecimalValue.ToString();
}

//Other code here

}

Open in new window



Thank you for your help.
0
 
AndyAinscowFreelance programmer / ConsultantCommented:
I'm not clear.
Are you still getting errors?
Is something not working the way you expect it to?
0
 
Salim FayadCommented:
It depends how are you filling the List<Report> from the database. If this decimal property in C# is nullable, then you can check if null
value.someDecimalValue == null

Open in new window

, if not, then you might need to check it with the
Decimal.MinValue

Open in new window

, so it becomes
value.someDecimalValue == Decimal.MinValue

Open in new window

0
 
iNetBlazerAuthor Commented:
Correction... I forgot to wright "HasValue"

foreach (var value in report)
{
  string dot = ".";
  string reportValue;

if (!value.someDecimalValue.HasValue)
{
  reportValue = dot;
}
else
{
  reportValue = value.someDecimalValue.ToString();
}

//Other code here

}

Open in new window

0
All Courses

From novice to tech pro — start learning today.