How to evaluate expression dynamically in c#

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Dear sir i have a datatable with component and farmula and i have Total

Total=12000

Component     Farmula
   CA          800Rs
   IN          50%Rest
   Basic       40%Total
   HRA         40%Basic
   SA          50%Rest

now i want all component value Like
and
calculation is
Rest=Total-(CA+Basic+HRA)=12000-(800+4800+1920)=4480

CA= 800RS = 800
IN= 2240 =50%Rest = 50%4480
Basic= 4800 =40%Total = 40%12000
HRA= 1920 =40%Basic = 40%4800
Sa= 2240 = 50%Rest = 50%4480

Posted 25-May-15 4:37am

maneesh katiyar

Updated 25-May-15 20:10pm

vJay Yadav

v4

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Comments

Sergey Alexandrovich Kryukov 25-May-15 11:09am

You need to explain what is supposed to be code and what's input data. Are you going to create an expression during runtime and be able to evaluate it with different input? This is quite possible, but you need to explain where your "dynamic" is.
—SA

[no name] 25-May-15 11:53am

Do you mean the data in DataTable or SQL Table?

Maciej Los 25-May-15 17:17pm

Your requirements are not clear, especially the way you count IN and SA values. Please, use "Improve question" widget to update your question.

Abhipal Singh 26-May-15 1:30am

I can understand your calculations. However, the million dollar question is.. where are you stuck?

Please answer SA's comment

maneesh katiyar 26-May-15 1:34am

Sir all the component and their's farmulas are dynamic.Means they may change for next time. So i am confused to what approach i use to replace all variable from farmula by Total.

Abhipal Singh 26-May-15 1:40am

I understand that your numeric values and formulas will change.
However, are all the strings CA, Rs, IN, Rest, Basic, Total, HRA, SA constant or will they change as well?
Also, is the calculation of "Rest" constant?
What will be the user input.. Just "Total" I suppose?
What will be the final output?

maneesh katiyar 26-May-15 1:43am

yes sir, User input is only Total. And He can create compnent and their respective farmula.

Abhipal Singh 26-May-15 1:46am

every user is going to have its own formula?
If yes, then are you keeping a seperate table for every user??!!!
what type of table are you using to save this formula? SQL, in memory, etc?
Also, answer my previous question.. :)

maneesh katiyar 26-May-15 1:54am

I am saving these farmula in sql server table for each user separately.
now i just want to replace dependecy of each farmula from user entered component to Total. because I have only value of Total. and you can see actually all farmulas depends on Total.

Abhipal Singh 26-May-15 2:00am

One table for each user!!!
I just hope you have very few users and you know which table will correspond to which user.

I have an answer to your question, however, before I post it, can you answer the below questions which I asked earlier..

Are all the strings CA, Rs, IN, Rest, Basic, Total, HRA, SA constant or will they change as well?
Is the calculation of "Rest" constant?
What will be the final output?

maneesh katiyar 26-May-15 2:03am

They also can change. noting is constant except Total

Abhipal Singh 26-May-15 2:18am

See, it works this way, to help you.. you need to help us by giving elaborate answers to questions. one liners are not descriptive and they dont help.
By the above statement it seems that nothing is constant. If that is the case then where are you saving formula of "Rest"?

I would suggest you do provide clear and descriptive answers if you expect solutions.

maneesh katiyar 26-May-15 2:21am

Actuall rest has no farmula. Rest will be calulated as
Rest=Total-(Sum of ALL farmula which has not cantain Rest)

maneesh katiyar 26-May-15 2:22am

In my Calculation you can understand all the procedure which i want to follow.

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Abhipal Singh · Answer 1 · 2015-05-25T23:59:00

1) I would suggest you to change your approach of having one table per user. This design is not scaleable. What you can do is, have one table with columns UserId, Component and Formula. By doing this you can filter out data based on user ids and get the component and Formula for an individual user.

C#

UserId Component Formula
1  	    CA        800Rs
1  	    IN        50%Rest
1  	    Basic	  40%Total
1  	    HRA       40%Basic
1  	    SA	      50%Rest
2  	    CA        900Rs
2  	    IN        10%Rest
2  	    Basic	  30%Total
2  	    HRA	      20%Basic
2  	    SA	      20%Rest

2) It is possible to dynamically evaluate your expressions. check the links below:
.Net Expression Evaluator using DynamicMethod[^]
Evaluate C# Code (Eval Function)[^]
You need to fetch the formulas from database and then feed them to your custom evaluator as described in links above.

maneesh katiyar · Answer 2 · 2015-05-26T01:38:00

C#

string Rest = "";
                for (int j = 0; j < dsAllFarmula.Tables[0].Rows.Count; j++)
                {
                   Component cmp = new Component();
                    cmp.ComponentName=dsAllFarmula.Tables[0].Rows[j]["SalaryComponent"].ToString();
                    cmp.CmponentValue = dsAllFarmula.Tables[0].Rows[j]["Farmula"].ToString();
                    Structure.Add(cmp);
                    if (!cmp.CmponentValue.Contains("Rest"))
                        Rest += "("+cmp.ComponentName+")+";
                   // double val= _model.Evaluate(cmp.CmponentValue);
                }
                Rest = Rest.Remove(Rest.Length-1);
                Rest = "Total-(" + Rest+")";
                foreach (var lom in Structure)
                {
                    Rest = Rest.Replace(lom.ComponentName, lom.CmponentValue);
                }

                foreach (var item in Structure)
                {
                    item.CmponentValue = item.CmponentValue.Replace("Rest", Rest);
                    foreach (var pre in Structure)
                        item.CmponentValue = item.CmponentValue.Replace(pre.ComponentName, pre.CmponentValue);

                }

How to evaluate expression dynamically in c#

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