In this article we will learn about how to filter data in datagridview. We can better understand this with an example.

Step 1
Create Windows Form with Textbox and DataGridView.

Step 2
In coding view, code as per the following code. Here, I give both code c# and vb.Net. You can choose as per your requirement(s).

Code as per Vb.Net
Imports System.Data.SqlClient

Public Class Form14
    Dim libconn As SqlConnection
    Dim daMain As SqlDataAdapter
    Dim dtMain As New DataSet
    Dim strQuery As String = ""
    Dim strConnectionString As String
    Dim otable As DataTable = New DataTable()

    Private Sub Form14_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        load_data()
        DataGridView1.AllowUserToAddRows = False
        DataGridView1.AllowUserToDeleteRows = False
    End Sub

    Private Sub load_data()
        Connetion()
        daMain = New SqlDataAdapter("Select * From Employee", libconn)
        dtMain.Clear()
        daMain.Fill(dtMain)
        DataGridView1.DataSource = dtMain.Tables(0)
        libconn.Close()
        DataGridView1.ClearSelection()
        TextBox1.Text = ""
        otable = GetOriginalDataTable()
    End Sub

    Public Function Connetion()
        strConnectionString = "Data Source=UDAY-LAPTOP;Initial Catalog=sqldemo;Integrated Security=true"
        libconn = New SqlConnection
        libconn.ConnectionString = strConnectionString
        If libconn.State <> ConnectionState.Open Then
            Try
                libconn.Open()
            Catch conn_error As SqlException
                MsgBox(conn_error.Message)
                Connetion = False
            End Try
        End If
        Connetion = True
    End Function

    Private Function GetOriginalDataTable() As DataTable
        Dim dtable As DataTable = New DataTable()
        For Each col As DataGridViewColumn In DataGridView1.Columns
            dtable.Columns.Add(col.Name)
        Next
        For Each row As DataGridViewRow In DataGridView1.Rows

            Dim dRow As DataRow = dtable.NewRow()
            Dim flag As Integer = -1
            For Each cell As DataGridViewCell In row.Cells
                dRow(cell.ColumnIndex) = cell.Value
            Next
            dtable.Rows.Add(dRow)
        Next
        Return dtable
    End Function

    Private Function SearchGrid()
        Dim dtable As DataTable = New DataTable()
        If TextBox1.Text.Length > 0 And DataGridView1.RowCount = 0 Then
            DataGridView1.DataSource = otable
        End If
        If TextBox1.Text.Length = 0 Then
            DataGridView1.DataSource = Nothing
            DataGridView1.DataSource = otable
        Else
            For Each col As DataGridViewColumn In DataGridView1.Columns
                dtable.Columns.Add(col.Name)
            Next
            For Each row As DataGridViewRow In DataGridView1.Rows
                Dim dRow As DataRow = dtable.NewRow()
                Dim flag As Integer = -1
                For Each cell As DataGridViewCell In row.Cells
                    dRow(cell.ColumnIndex) = cell.Value
                    Dim str As String = cell.Value.ToString().ToLower()
                    Dim str1 As String = TextBox1.Text.ToLower()
                    If str.Contains(str1.ToString()) = True Then
                        flag = 1
                    End If
                Next
                If flag = 1 Then
                    dtable.Rows.Add(dRow)
                End If
            Next
            DataGridView1.DataSource = Nothing
            DataGridView1.DataSource = dtable
        End If
        SearchGrid = True
    End Function

    Private Function HighlightGrid()
        If TextBox1.Text.Length = 0 Then
            For n As Integer = 0 To (DataGridView1.Rows.Count) - 1
                For m As Integer = 0 To (DataGridView1.Rows(n).Cells.Count) - 1
                    DataGridView1.Rows(n).Cells(m).Style.BackColor = SystemColors.Control
                Next
            Next
        Else
            For n As Integer = 0 To (DataGridView1.Rows.Count) - 1
                For m As Integer = 0 To (DataGridView1.Rows(n).Cells.Count) - 1
                    Dim str As String = DataGridView1.Rows(n).Cells(m).Value.ToString().ToLower()
                    Dim str1 As String = TextBox1.Text.ToLower()
                    If str.Contains(str1.ToString()) = True Then
                        DataGridView1.Rows(n).Cells(m).Style.BackColor = Color.Yellow
                    Else
                        DataGridView1.Rows(n).Cells(m).Style.BackColor = SystemColors.Control
                    End If
                Next
            Next
        End If
        HighlightGrid = True
    End Function

    Private Sub TextBox1_KeyUp(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyUp
        If e.KeyCode = Keys.Back Then
            DataGridView1.DataSource = otable
            SearchGrid()
            HighlightGrid()
            DataGridView1.ClearSelection()
        End If
    End Sub

    Private Sub TextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles TextBox1.TextChanged
        SearchGrid()
        HighlightGrid()
        DataGridView1.ClearSelection()
    End Sub

End Class

ASP.NET (C#)
Code as per C#
using System.Data.SqlClient;

public class Form14
{
    private SqlConnection libconn;
    private SqlDataAdapter daMain;
    private DataSet dtMain = new DataSet();
    private string strQuery = "";
    private string strConnectionString;
    private DataTable otable = new DataTable();

    private void Form14_Load(System.Object sender, System.EventArgs e)
    {
        load_data();
        DataGridView1.AllowUserToAddRows = false;
        DataGridView1.AllowUserToDeleteRows = false;
    }

    private void load_data()
    {
        Connetion();
        daMain = new SqlDataAdapter("Select * From Employee", libconn);
        dtMain.Clear();
        daMain.Fill(dtMain);
        DataGridView1.DataSource = dtMain.Tables(0);
        libconn.Close();
        DataGridView1.ClearSelection();
        TextBox1.Text = "";
        otable = GetOriginalDataTable();
    }

    public void Connetion()
    {
        strConnectionString = "Data Source=UDAY-LAPTOP;Initial Catalog=sqldemo;Integrated Security=true";
        libconn = new SqlConnection();
        libconn.ConnectionString = strConnectionString;
        if (libconn.State != ConnectionState.Open)
        {
            try
            {
                libconn.Open();
            }
            catch (SqlException conn_error)
            {
                Interaction.MsgBox(conn_error.Message);
                Connetion = false;
            }
        }
        Connetion = true;
    }

    private DataTable GetOriginalDataTable()
    {
        DataTable dtable = new DataTable();
        foreach (DataGridViewColumn col in DataGridView1.Columns)
            dtable.Columns.Add(col.Name);
        foreach (DataGridViewRow row in DataGridView1.Rows)
        {
            DataRow dRow = dtable.NewRow();
            int flag = -1;
            foreach (DataGridViewCell cell in row.Cells)
                dRow(cell.ColumnIndex) = cell.Value;
            dtable.Rows.Add(dRow);
        }
        return dtable;
    }

    private void SearchGrid()
    {
        DataTable dtable = new DataTable();
        if (TextBox1.Text.Length > 0 & DataGridView1.RowCount == 0)
            DataGridView1.DataSource = otable;
        if (TextBox1.Text.Length == 0)
        {
            DataGridView1.DataSource = null;
            DataGridView1.DataSource = otable;
        }
        else
        {
            foreach (DataGridViewColumn col in DataGridView1.Columns)
                dtable.Columns.Add(col.Name);
            foreach (DataGridViewRow row in DataGridView1.Rows)
            {
                DataRow dRow = dtable.NewRow();
                int flag = -1;
                foreach (DataGridViewCell cell in row.Cells)
                {
                    dRow(cell.ColumnIndex) = cell.Value;
                    string str = cell.Value.ToString().ToLower();
                    string str1 = TextBox1.Text.ToLower();
                    if (str.Contains(str1.ToString()) == true)
                        flag = 1;
                }
                if (flag == 1)
                    dtable.Rows.Add(dRow);
            }
            DataGridView1.DataSource = null;
            DataGridView1.DataSource = dtable;
        }
        SearchGrid = true;
    }

    private void HighlightGrid()
    {
        if (TextBox1.Text.Length == 0)
        {
            for (int n = 0; n <= (DataGridView1.Rows.Count) - 1; n++)
            {
                for (int m = 0; m <= (DataGridView1.Rows(n).Cells.Count) - 1; m++)
                    DataGridView1.Rows(n).Cells(m).Style.BackColor = SystemColors.Control;
            }
        }
        else
            for (int n = 0; n <= (DataGridView1.Rows.Count) - 1; n++)
            {
                for (int m = 0; m <= (DataGridView1.Rows(n).Cells.Count) - 1; m++)
                {
                    string str = DataGridView1.Rows(n).Cells(m).Value.ToString().ToLower();
                    string str1 = TextBox1.Text.ToLower();
                    if (str.Contains(str1.ToString()) == true)
                        DataGridView1.Rows(n).Cells(m).Style.BackColor = Color.Yellow;
                    else
                        DataGridView1.Rows(n).Cells(m).Style.BackColor = SystemColors.Control;
                }
            }
        HighlightGrid = true;
    }

    private void TextBox1_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Back)
        {
            DataGridView1.DataSource = otable;
            SearchGrid();
            HighlightGrid();
            DataGridView1.ClearSelection();
        }
    }

    private void TextBox1_TextChanged(System.Object sender, System.EventArgs e)
    {
        SearchGrid();
        HighlightGrid();
        DataGridView1.ClearSelection();
    }
}

Output 1
When you run the application, by default all data will be loaded in datagridview as per the following:

Final Output
In Textbox, when I type IT, the following records will be filtered:

Final Output
In Textbox, when I type IT, the following records will be filtered: