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DataView

A DataView is a live, filtered and sorted window onto a DataTable — no extra database query required.

Intermediate 5 min Lesson 17 of 32Examples use Microsoft.Data.SqlClient on .NET 9 with SQL Server 2022.
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On this page · 5 min · Intermediate

On this page

  1. In simple words
  2. Learning objectives
  3. Explanation
  4. Code example
  5. Step by step
  6. Real-world use
  7. Common mistakes
  8. Best practices
  9. Remember this
  10. Practice exercise
  11. Mini quiz
  12. Related topics
  13. My notes
Reading time
5 min
Difficulty
Intermediate
Updated
Oct 29, 2026

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Interview questions

In simple words#

A DataView is a coloured filter sheet over your photocopy: show only some rows, in a chosen order, without changing the copy.

RowFilter
Filter rows in memory.
Sort
Order rows in memory.
ToTable
Copy the visible rows to a new table.

Learning objectives#

  • Filter rows with RowFilter
  • Sort with Sort
  • Find rows by the sort key
  • Create a new table from a view

Explanation#

RowFilter uses a simple expression language: "Price > 1000 AND Name LIKE '%o%'". String values go in single quotes; dates in #…#.

Sort takes column names with ASC or DESC, e.g. "Price DESC, Name".

RowStateFilter shows rows by state — useful for “show only unsaved changes”.

ToTable copies the visible rows (optionally only some columns, optionally distinct) into a new DataTable.

Code example: Filtering and sorting in memory#

C#DataViewDemo.cs Illustrative
var view = new DataView(table)
{
    RowFilter = "Price >= 2000",
    Sort = "Price DESC",
};
foreach (DataRowView row in view)
    Console.WriteLine(
quot;{row["Name"]}: ₹{row["Price"]}");


view.RowFilter = "Name LIKE 'M%'";
Console.WriteLine(
quot;Starting with M: {view.Count}");


DataTable names = view.ToTable(distinct: true, "Name");
Console.WriteLine(
quot;Copied {names.Rows.Count} name(s) into a new table");
Expected output
Laptop: ₹55000.00
Keyboard: ₹2200.00
Starting with M: 1
Copied 1 name(s) into a new table

This example is illustrative. Copy or download it and run it in your own environment; the expected output is shown above.

Step-by-step explanation#

  1. The view shows products of ₹2000 or more, most expensive first.
  2. Changing RowFilter updates the view immediately.
  3. ToTable copies only the Name column of visible rows.

Real-world use case#

A WinForms or WPF grid bound to a DataView filters instantly as the user types in a search box.

Common mistakes#

Building RowFilter from raw input

A quote in the input breaks the expression. Escape single quotes (' → '') or filter with LINQ.

Expecting the database to change

A DataView filters the in-memory copy only.

Best practices#

  • Use DataView for UI filtering of small tables
  • Escape quotes in filter values
  • Use LINQ to DataSet for complex logic
  • Filter large data in SQL instead

Remember this#

DataView = filtered + sorted window on a DataTable.

RowFilter strings use single quotes.

ToTable = copy what you see.

Practice exercise#

Your task: Show only modified rows in a view.

Show solution
C# Illustrative
var changes = new DataView(table) { RowStateFilter = DataViewRowState.ModifiedCurrent };

Mini quiz#

DataView quizMultiple choice Question 1 of 1

Which property sorts a DataView?

Score so far: 0/0

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My notes#

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