In this article I will explain with an example, how to search (filter) DataGridView on TextBox KeyPress in Windows Forms (WinForms) Application using C# and VB.Net.
By default, the DataGridView will show all records. As soon as user starts to type in the TextBox, the records will be searched in Database and the DataGridView rows will be filtered in Windows Forms (WinForms) Application using C# and VB.Net.
 
 

Database

Here I am making use of Microsoft’s Northwind Database. You can download it from here.
Download and install Northwind Database
 
 

Form Design

The Form consists of a TextBox and a DataGridView control.
Search (Filter) DataGridView on TextBox KeyPress in Windows Forms Application using C# and VB.Net
 
 

Namespaces

You will need to import the following namespaces.
C#
using System.Data;
using System.Data.SqlClient;
 
VB.Net
Imports System.Data
Imports System.Data.SqlClient
 
 

Search (Filter) DataGridView on TextBox KeyPress in Windows Forms Application

The DataGridView is populated using the PopulateDataGridView function in two places, first in the Form Load event handler and second in the KeyUp event handler of the TextBox.
The SQL Query is created in such a way that it will return all records if the TextBox value is Blank and will return filtered records when the TextBox has a value.
Inside the PopulateDataGridView function, the SQL Query is executed and the results are populated into a DataTable.
C#
private void Form1_Load(object sender, EventArgs e)
{
     dataGridView1.DataSource = this.PopulateDataGridView();
}
 
private void txtName_KeyUp(object sender, KeyEventArgs e)
{
     dataGridView1.DataSource = this.PopulateDataGridView();
}
 
private DataTable PopulateDataGridView()
{
    string sql = "SELECT CustomerID, ContactName, Country FROM Customers";
    sql += " WHERE ContactName LIKE '%' + @ContactName + '%'";
    sql += " OR @ContactName = ''";
    string constr = @"Data Source=.\SQL2019;Initial Catalog=Northwind;User ID=sa;Password=pass@123";
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(sql, con))
        {
            cmd.Parameters.AddWithValue("@ContactName", txtName.Text.Trim());
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                DataTable dt = new DataTable();
                sda.Fill(dt);
                return dt;
            }
        }
    }
}
 
VB.Net
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
     dataGridView1.DataSource = Me.PopulateDataGridView()
End Sub
 
Private Sub txtName_KeyUp(sender As System.Object, e As System.Windows.Forms.KeyEventArgs) Handles txtName.KeyUp
     dataGridView1.DataSource = Me.PopulateDataGridView()
End Sub
 
Private Function PopulateDataGridView() As DataTable
    Dim sql As String = "SELECT CustomerID, ContactName, Country FROM Customers"
    sql &= " WHERE ContactName LIKE '%' + @ContactName + '%'"
    sql &= " OR @ContactName = ''"
    Dim constr As String = "Data Source=.\SQL2019;Initial Catalog=Northwind;User ID=sa;Password=pass@123"
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(sql, con)
            cmd.Parameters.AddWithValue("@ContactName", txtName.Text.Trim())
            Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                Dim dt As DataTable = New DataTable()
                sda.Fill(dt)
                Return dt
            End Using
        End Using
    End Using
End Function
 
 

Screenshot

Search (Filter) DataGridView on TextBox KeyPress in Windows Forms Application using C# and VB.Net
 
 

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