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C# Convert List to DataTable (DataGridView)

This C# example program converts a List to a DataTable instance. It uses DataGridView.
Convert List, DataTable. The DataGridView control can display a List. This can be done by converting the List to a DataTable first.
Some notes. With some custom List-to-DataTable conversion logic, we get the best performance from the DataGridView by using the DataSource property.
An example. This example shows a List of string arrays. This is a data structure that could be parsed from a text file easily, as with the Split method.

Method: We introduce the ConvertListToDataTable method, which converts a List<string[]> to a DataTable.

Array

Here: We create a new empty DataTable. Next, we find the maximum number of columns that will be required by looping through the input List.

Then: We add those columns, and then add all the rows. We return the DataTable.

C# program that converts List to DataTable for DataGridView using System; using System.Collections.Generic; using System.Data; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { // Example list. List<string[]> list = new List<string[]>(); list.Add(new string[] { "Column 1", "Column 2", "Column 3" }); list.Add(new string[] { "Row 2", "Row 2" }); list.Add(new string[] { "Row 3" }); // Convert to DataTable. DataTable table = ConvertListToDataTable(list); dataGridView1.DataSource = table; } static DataTable ConvertListToDataTable(List<string[]> list) { // New table. DataTable table = new DataTable(); // Get max columns. int columns = 0; foreach (var array in list) { if (array.Length > columns) { columns = array.Length; } } // Add columns. for (int i = 0; i < columns; i++) { table.Columns.Add(); } // Add rows. foreach (var array in list) { table.Rows.Add(array); } return table; } } }
Assign to DataSource. Once we have a DataTable instance, it is appropriate to assign it to the DataSource property. Assigning the List<string[]> to the DataSource will not work correctly.DataSource

Note: The DataSource provides the best performance for displaying large amounts of data instantly in a DataGridView.

Warning: If you were to add Columns and Rows individually, slowdowns are more likely to occur.

Discussion. DataTable can be used as an optimization. Using controls in Windows Forms or WPF directly often results in rendering.

However: This is often much slower, and more processor-intensive, than in-memory operations.

So: When using DataGridView or similar controls, processing the data first seems like it might be slower, but it ends up much faster.

DataGridView
A summary. We converted a List of string arrays into a DataTable. This yielded a collection that can be displayed in a DataGridView with the DataSource property. Our code was effective.ListDataTable
You could imperatively add rows and columns to the DataGridView. But this can be slower. Building a collection in-memory with a DataTable is often more effective.
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