C# String text into another string variable

Question

I have this code:

string str1 = "Button1";
string str2 = "Button2";
string str3 = str1 + " " + str2;

What I want is to copy the text from str3 ("Button1 Button2") so that

string str4 = "Button1 Button2";

Why do I want such a thing, you may ask? It's because of this method that I'm trying to develop:

    public void SearchNumpadNumbersOnMyApp(double valueRepoItemName)
    {   
        valueRepoItemName = Math.Abs(valueRepoItemName);        
        string repoItemName;
        string result = string.Format("{0:F1}", valueRepoItemName);
        int length = result.Length;         
        char[] arrayOfCharacters = result.ToCharArray();

        for (int i = 0; i < length; i++)
        {                   
        repoItemName = "Button" + arrayOfCharacters[i].ToString();

        // Query RepoItemInfo objects based on the repository item name 
        IEnumerable<RepoItemInfo> myQuery = from things in repo.FO.FLOW2FO.Container2.SelfInfo.Children
                    where ReferenceEquals(things.Name, repoItemName)
                    select things;
        // Create "unkown" adapter for the first found element and click it
        myQuery.First().CreateAdapter<Unknown>(true).Click();               
        }               
    }

When I pass repoItemName to

where ReferenceEquals(things.Name, repoItemName)

I get the error message "Sequence contains no elements", and this occurs when I try to pass repoItemName string. This is the same as passing

where ReferenceEquals(things.Name, "Button" + arrayOfCharacters[i].ToString())

and this is the reason why I'm getting the error. So, what I want is to pass the actual text of the string and not its reference. I want it to be, for example, like this:

where ReferenceEquals(things.Name, "Button5")

Being "Button5" the string structure built with:

repoItemName = "Button" + arrayOfCharacters[i].ToString();

By the way, I already tried:

String.Copy();
String.Clone();

but nothing seems to do what I really want.

You likely want to replace ReferenceEquals(things.Name, repoItemName) with string.Equals(things.Name, repoItemName) because you want to compare the equality of what the strings represent, not the equality of where each string is residing in memory. — Quantic
– Quantic, Commented Jan 3, 2017 at 16:40
Why are you checking references instead of the actual value? as @Quantic said you just need to do a string equals... — Nilesh
– Nilesh, Commented Jan 3, 2017 at 16:44
You my friend, just solved my problem, thank you so much!!! :) Massive hug for you! — kenzoviski
– kenzoviski, Commented Jan 3, 2017 at 16:44
No need for the char array repoItemName = "Button" + result[i]; — Edward
– Edward, Commented Jan 3, 2017 at 16:59

kenzoviski · Accepted Answer · 2017-01-03 16:56:57Z

1

The solution to my problem was this:

    IEnumerable<RepoItemInfo> myQuery = from things in repo.FO.FLOW2FO.Container2.SelfInfo.Children
        where String.Equals(things.Name, repoItemName)
        select things;

Thanks to all of you guys that helped me :)

answered Jan 3, 2017 at 16:56

kenzoviski

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Comments

René Vogt · Accepted Answer · 2017-01-03 16:57:22Z

0

You need to change this

IEnumerable<RepoItemInfo> myQuery = from things in repo.FO.FLOW2FO.Container2.SelfInfo.Children
                where ReferenceEquals(things.Name, repoItemName)
                select things;

to

IEnumerable<RepoItemInfo> myQuery = from things in repo.FO.FLOW2FO.Container2.SelfInfo.Children
                where things.Name == repoItemName
                select things;

You want to compare the content of the strings, not the references. A string in C# is an immutable class. So

string str1 = "button1 button2";
string str2 = new string(str1.ToCharArray());

str1 and str2 are equal strings, but the two variables reference two different instances of string. Thatswhy ReferenceEquals(str1, str2) will always return false.

edited Jan 3, 2017 at 16:57

answered Jan 3, 2017 at 16:44

René Vogt

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4 Comments

Quantic Over a year ago

Just FYI your example

string str1 = "button1 button2";         string str2 = "button1 " + "button2";         Console.WriteLine(ReferenceEquals(str1, str2));

returns True, I assume because of this.

René Vogt Over a year ago

@Quantic I already feared that this example is not good, because of those damn smart compilers. I changed the example, but now I'm not sure if it's not more confusing...

kenzoviski Over a year ago

@René Vogt I swapped my code with your code and it didn't compiled. Although I already found the solution provided by the user Quantic

René Vogt Over a year ago

@kenzoviski that's because I used the equals keyword in wrong context. Changed it to ==, but you may use the string.Equals() from Quantic as well.

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