🔤 Razor C# – Variables – Declare and Use Variables in Razor Views

🧲 Introduction – What Are Razor Variables?

In Razor syntax, variables allow you to store and manipulate data inside .cshtml views using C#. You can use them to hold strings, numbers, lists, objects, or even results of calculations and conditions. Razor variables are commonly used in templates to display dynamic content.

🎯 In this guide, you’ll learn:

• How to declare variables in Razor
• Different ways to use variables inline or in code blocks
• Practical examples of variable usage in views
• Best practices for using variables efficiently in Razor pages

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🧱 Declaring Variables in Razor

Use @{ ... } code blocks to define variables in Razor views.

@{
    string name = "Vaibhav";
    int age = 28;
}
<p>Name: @name</p>
<p>Age: @age</p>

🧪 Output:

Name: Vaibhav  
Age: 28

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🧪 Example – Variable in Expressions

@{
    int a = 10;
    int b = 20;
    int sum = a + b;
}
<p>Total: @sum</p>

🔍 Razor renders @sum as 30.

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🔁 Variable Inside Loops and Conditions

You can declare and update variables inside loops and conditionals:

@{
    int counter = 1;
}
<ul>
@while (counter <= 3)
{
    <li>Item @counter</li>
    counter++;
}
</ul>

🧪 Output:

Item 1  
Item 2  
Item 3

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📦 Working with String Interpolation

@{
    string product = "Laptop";
    int price = 50000;
}
<p>@($"Product: {product}, Price: ₹{price}")</p>

🧪 Output: Product: Laptop, Price: ₹50000

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💬 Declaring Complex Variables (Arrays, Lists)

@{
    string[] colors = { "Red", "Green", "Blue" };
}
@foreach (var color in colors)
{
    <p>@color</p>
}

✅ You can also use:

• List<string>
• Dictionary<TKey, TValue>
• Custom model types

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🧬 Scope of Razor Variables

Location	Scope Description
Inside @{}	Local to the block/view
Inside @functions	Reusable methods and shared variables
In @model properties	Passed from controller or page model

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⚙️ Setting Variables Dynamically

@{
    string greeting = DateTime.Now.Hour < 12 ? "Good morning" : "Good evening";
}
<p>@greeting</p>

🧪 Output depends on the server time.

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❌ Common Mistakes to Avoid

❌ Mistake	✅ Correct Usage
string name = "John" outside @{}	Use @{ string name = "John"; }
Using @ inside @{} unnecessarily	Avoid @name inside code blocks
Omitting ; in code lines	End all C# lines in Razor with ;

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📘 Best Practices for Razor Variables

✅ Do:

• Keep variable names clear and descriptive
• Use inline expressions (@variable) for simple outputs
• Separate logic-heavy variables into the controller or page model

❌ Avoid:

• Placing business logic in Razor views
• Re-declaring variables inside loops unless needed
• Using ViewBag excessively when you have @model

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📌 Summary – Recap & Next Steps

Razor variables let you work with C# inside your views for displaying dynamic data, performing calculations, and looping through lists. They improve readability and control within .cshtml pages.

🔍 Key Takeaways:

• Declare variables in @{} and render with @variable
• Use variables inside loops, conditions, and interpolations
• Keep Razor logic simple and clean

⚙️ Real-world Use Cases:

• Displaying user profile info
• Looping through product lists
• Conditionally formatting UI content

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❓ FAQs – Razor C# Variables

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❓ Can I declare variables outside @{} in Razor?
✅ No. All C# variables must be declared within a Razor code block using @{}.

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❓ How do I access variables defined in the controller?
✅ Use @model to strongly type the view and access properties via Model.PropertyName.

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❓ Can I use var to declare variables in Razor?
✅ Yes. You can use var name = "John"; just like in C#.

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❓ How do I combine strings in Razor?
✅ Use either + operator or string interpolation: @("Name: " + name) or $"Name: {name}".

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