How to evalute a math expression given in string form in C#?

Question

I'm fairly new to programming and c#. I have a problem with a simple calculator program I'm trying to write in visual studio c#. I want to convert my text with numbers and math operators into a number. All my attempts so far have led to no success. I have tried:

Double.Parse()
Convert.Int32()
Convert.Double()

Here are some images of my code: Pic One Pic Two

Any help would be much appreciated, if there is any extra information you need I would be happy to provide it.

-Retro_Goat

Xavier · Answer 1 · 2021-03-05T00:23:08.113

-1

For Pic 1 C# can not take an equation string and convert it to a result, it can take values in an equation form and convert it to a result, i.e.

int val = Convert.ToInt32((7 + 3) * 3.5);

If you have an equation string you will need to cycle through the string an separate the values and the operations and process them as values or use a processing object, see StackOverflow link

For Pic 2

        double val = 0;
        if(double.TryParse(lblDisplay.Text, out val))
        {
            // val is set to the string value
        }
        else 
        {
           // The string was not a valid number
        }

edited Mar 05 '21 at 00:23

answered Mar 05 '21 at 00:17

Xavier

1,383
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6

You can evaluate strings as expressions in c# – Crowcoder Mar 05 '21 at 00:19
int val = Convert.ToInt32("7 + 3"); is not valid in C#, which is what I was trying to impart – Xavier Mar 05 '21 at 00:21
No, not like that. Like in the link I proposed as a duplicate. – Crowcoder Mar 05 '21 at 00:22

How to evalute a math expression given in string form in C#?

1 Answers1