Using DataView in C# to Filter Rows in a DataTable

Working with DataTable objects in C# frequently requires dynamic data filtering without changing the underlying table. This is why the DataView class was created. You can effectively sort, filter, and search rows with its view of a data table.

 

Understanding the Scenario

Consider you have a DataTable called dt containing columns like:

• Symbol

• Category

• opendatetime

• closedatetime

• FloorPrice

• CeilingPrice

• asbanonasba

You want to filter rows where a specific column matches a value.

Using DataView to Filter Rows

else
{
    // Create a DataView from the DataTable
    DataView dv = dt.DefaultView;

    // Apply a filter condition
    dv.RowFilter = "asbanonasba = '1'";

    // Convert the filtered view back to a DataTable
    DataTable dts = dv.ToTable();
}

Step-by-Step Explanation

1. Create a DataView

DataView dv = dt.DefaultView;

• DefaultView creates a DataView object linked to the DataTable.

• Changes in the DataView do not modify the original DataTable.

2. Set the RowFilter

dv.RowFilter = "asbanonasba = '1'";

• RowFilter is similar to a SQL WHERE clause.

• Syntax

"ColumnName operator value"

• Examples

dv.RowFilter = "Category = 'IND'";         // Filter by text
dv.RowFilter = "FloorPrice > 100";         // Filter numeric values
dv.RowFilter = "opendatetime >= '2025-10-01'";  // Filter dates

3. Convert the Filtered View Back to a DataTable

DataTable dts = dv.ToTable();

• dv.ToTable() creates a new DataTable containing only the rows that satisfy the RowFilter.

• You can now use dts for binding to UI controls, exporting, or further processing.

Optional: Selecting Specific Columns and Distinct Rows

You can also select only certain columns or remove duplicates using the overloaded ToTable method:

DataTable distinctTable = dv.ToTable(
    true,                           // distinct rows only
    "Symbol", "Category", "FloorPrice"  // columns to include
);

Practical Example

Suppose your DataTable has the following data:

Symbol	Category	asbanonasba
ABC	IND	1
DEF	IND	0
XYZ	FMCG	1

Filtering with

dv.RowFilter = "asbanonasba = '1'";

The resulting DataTable will contain:

Symbol	Category	asbanonasba
ABC	IND	1
XYZ	FMCG	1

Tips and Best Practices

1. Always check for column names in the filter string — typos will throw exceptions.

2. String values must be enclosed in single quotes ' '.

3. DateTime values must be in MM/dd/yyyy format or use # in US format:

dv.RowFilter = "opendatetime >= #10/01/2025#";

4. For numeric columns, quotes are not needed:

dv.RowFilter = "CeilingPrice >= 500";

5. DataView vs LINQ: DataView is faster for UI-bound tables; LINQ to DataSet is more flexible for complex queries.

Conclusion

Using DataView and its RowFilter property is a simple and effective way to filter rows in a DataTable without modifying the original data. It’s particularly useful for binding filtered data to grids, reports, or exporting results.

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