Eval vs Bind: Difference and Comparison

In 2002, Microsoft launched ASP.NET. This was a web application that allowed software programmers to build robust websites easily. Since then, the world of software programming has changed for the better.

Eval and Bind are two functions on ASP.NET that are applied during the process of data binding. Not only do these benefit programmers, but web designers as well.

Key Takeaways

1. Eval is a function that evaluates a string as code, while bind is a function that creates a new function with a specific value and arguments.
2. Eval can execute arbitrary code, while bind creates a new function with a specific context.
3. If used improperly, eval can be a security risk, while bind is safe.

Eval vs Bind

The difference between Eval and Bind is that the Eval function on ASP.NET only allows a user or programmer to control the display values. This means that the Eval function is for reading purposes only. On the other hand, the Bind function allows users to control display values as well as update or modify the data.

In some programming languages, the full form of Eval is English evaluation. It is a function that can evaluate a string as well as return corresponding results as if the string were an expression.

The input to Eval may also be a structured representation of code instead of a string. In computer programming, to make associations between two or more programming items or value objects means to Bind.

This is done only for some extent of time and place. In simple terms, while building an application, lots of routines, subroutines, classes, and modules are used. To bind means to put these pieces together.

Comparison Table

Parameters of Comparison	Eval	Bind
Meaning	Eval is a function that can be used to evaluate a string and get corresponding results.	The bind function allows users to make links between two or more programming items or value objects.
Uses	Eval allows a user to control display value.	Bind allows a user to control display value and also update it.
Binding	Only one-way binding is done by the Eval function.	Two-way binding is done with the help of the Bind function.
Class	Eval is a method that is protected and defined on the Template control class.	The method Bind does not belong to any particular class.
ID	Eval function does not require the ID of certain controls.	The bind function always requires the ID of certain controls.

What is Eval?

In some programming languages, Eval is a function that can be employed to evaluate a certain string. Along with this, it also yields the corresponding results just as though the string were an expression.

Another way to understand what Eval is is by considering that Eval is a method of binding that allows a user to control only the display value.

Eval carries out only one-way binding. This means that it is a type of ‘read-only’ function. With Eval, a user is not able to update or modify the display value in any way.

The method is protected and defined on the Template control class. Moreover, Eval does not require any sort of ID of certain controls. Another aspect to think of while using the Eval method for binding is security.

Using the function with data from a source that is not trustworthy may lead to risks and vulnerabilities when it comes to security. To rectify security breaches, a user must escape all the data that has been used with Eval.

Eval is always implemented with a similar interpreter as usual code with other interpreted languages. However, in the case of compiled languages, other unrelated interpreters are also used at times.

What is Bind?

In the world of computer programming, the function bind means to make links between two or more programming items or value objects.

The function allows a programmer to control the display value as well as update, rectify and modify it. Basically, in simple terms, Bind allows a user to carry out two-way binding.

It is safe to say that the Bind method does not belong to any particular class. Moreover, the function always requires the ID of certain controls.

In ASP.NET, GrandView, DetailsView, FormView, and other data-bound controls can use the updating, deleting, and inserting operations by themselves.

Another aspect while using these data-bound controls is that these templates allow a user to extract values from child controls and even pass them to the data source control.

An appropriate command is then carried out by the data source control for the database. By dint of this, the bind function must always be used with InsertItemTemplate and EditItemTemplate of a data-bound control.

The Bind method is to be used along with input controls, that too in the editing mode. In case a data-bound control creates an input control in the form of its rendering, then input values can also be extracted.

Main Differences Between Eval and Bind

1. Eval allows a user to evaluate a string and get results, while Bind is used to link two or more programming items or value objects.
2. Eval only allows a user to control display value while Bind allows to control, insert, delete, update and modify it.
3. Eval allows just one-way binding. On the other hand, Bind allows two-way data binding.
4. Eval is defined on the Template control class, while Bind is not defined on any sort of class.
5. The eval function does not require the ID of certain controls, while the Bind function does.

References

1. https://link.springer.com/chapter/10.1007/978-3-642-12251-4_18
2. https://link.springer.com/chapter/10.1007/978-3-642-11957-6_30