C#实现只读DataGridView内置特定列搜索（无需TextBox）

I get it, you want to let users type directly into your read-only DataGridView to filter rows where the Name column matches their input—no extra TextBox needed. Here's a step-by-step solution that works for both bound and unbound DataGridViews:

Step 1: Set Up Variables and Initialize the Control #

First, add form-level variables to track the search text and a timer to reset the search after inactivity. Then set up your DataGridView (example includes sample data for testing):

using System;
using System.Data;
using System.Windows.Forms;

namespace DataGridViewSearch
{
    public partial class MainForm : Form
    {
        private string _currentSearch = string.Empty;
        private Timer _searchResetTimer;

        public MainForm()
        {
            InitializeComponent();
            Load += MainForm_Load;
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            // Configure the search reset timer (clears search after 2 seconds of inactivity)
            _searchResetTimer = new Timer
            {
                Interval = 2000 // Adjust this value (in milliseconds) as needed
            };
            _searchResetTimer.Tick += SearchResetTimer_Tick;

            // Set up sample DataGridView (replace with your actual data source)
            DataTable studentTable = new DataTable();
            studentTable.Columns.Add("Roll No", typeof(int));
            studentTable.Columns.Add("Name", typeof(string));
            studentTable.Columns.Add("Surname", typeof(string));

            // Add sample rows
            studentTable.Rows.Add(1, "Mohan", "Sharma");
            studentTable.Rows.Add(2, "Rahul", "Verma");
            studentTable.Rows.Add(3, "Mohan", "Singh");
            studentTable.Rows.Add(4, "Priya", "Mehta");

            // Bind data to DataGridView and make it read-only
            dataGridView1.DataSource = studentTable;
            dataGridView1.ReadOnly = true;
            dataGridView1.KeyPress += DataGridView1_KeyPress;

            // Ensure the DataGridView has focus to receive key presses
            dataGridView1.Focus();
        }
    }
}

Step 2: Capture Key Presses to Build Search Text #

Handle the KeyPress event to build the search string (including backspace support):

private void DataGridView1_KeyPress(object sender, KeyPressEventArgs e)
{
    // Handle backspace to remove the last character from the search text
    if (e.KeyChar == (char)Keys.Back)
    {
        if (_currentSearch.Length > 0)
        {
            _currentSearch = _currentSearch.Substring(0, _currentSearch.Length - 1);
        }
    }
    // Add printable characters (letters, numbers, spaces) to the search text
    else if (char.IsLetterOrDigit(e.KeyChar) || char.IsWhiteSpace(e.KeyChar))
    {
        _currentSearch += e.KeyChar;
    }

    // Restart the timer to reset search if user stops typing
    _searchResetTimer.Stop();
    _searchResetTimer.Start();

    // Apply the filter immediately after each key press
    ApplySearchFilter();
}

Step 3: Reset Search After Inactivity #

The timer clears the search text if the user stops typing for the specified interval:

private void SearchResetTimer_Tick(object sender, EventArgs e)
{
    _currentSearch = string.Empty;
    ApplySearchFilter();
    _searchResetTimer.Stop();
}

Step 4: Apply the Search Filter #

This method filters rows based on the current search text. It supports both bound (DataTable) and unbound DataGridViews:

private void ApplySearchFilter()
{
    // Handle bound DataGridView (connected to DataTable)
    if (dataGridView1.DataSource is DataTable studentTable)
    {
        DataView studentView = studentTable.DefaultView;
        
        if (string.IsNullOrEmpty(_currentSearch))
        {
            // Show all rows if search text is empty
            studentView.RowFilter = string.Empty;
        }
        else
        {
            // Escape single quotes to avoid syntax errors in RowFilter
            string escapedSearch = _currentSearch.Replace("'", "''");
            
            // Option 1: Exact match (case-insensitive)
            studentView.RowFilter = $"UPPER(Name) = '{escapedSearch.ToUpper()}'";
            
            // Option 2: Partial match (contains search text, case-insensitive)
            // studentView.RowFilter = $"UPPER(Name) LIKE '%{escapedSearch.ToUpper()}%'";
        }
    }
    // Handle unbound DataGridView
    else
    {
        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            if (!row.IsNewRow)
            {
                string nameValue = row.Cells["Name"].Value?.ToString() ?? string.Empty;
                
                if (string.IsNullOrEmpty(_currentSearch))
                {
                    row.Visible = true;
                }
                else
                {
                    // Option 1: Exact match (case-insensitive)
                    row.Visible = nameValue.Equals(_currentSearch, StringComparison.OrdinalIgnoreCase);
                    
                    // Option 2: Partial match (contains search text, case-insensitive)
                    // row.Visible = nameValue.Contains(_currentSearch, StringComparison.OrdinalIgnoreCase);
                }
            }
        }
    }
}

Key Notes #

• Case Sensitivity: The code uses case-insensitive matching by default. Adjust the StringComparison or remove UPPER() calls if you need case-sensitive search.
• Special Characters: The escapedSearch variable handles single quotes in the search text to prevent syntax errors in the DataView RowFilter.
• Timer Interval: Modify the _searchResetTimer.Interval value to change how long the search stays active after the user stops typing (2000ms = 2 seconds).
• Focus: Make sure the DataGridView has focus when the form loads so it can receive key presses.

This solution lets users type directly into the read-only DataGridView, filters rows in real-time, and clears the search automatically after inactivity—perfect for your use case!

内容的提问来源于stack exchange，提问作者Mohan Lalwani