Hi Fenil,

To display the filtered record id DataGridView you need to assign DataTable/DataSet as DataSource for DataGridView.

Check this example. Now please take its reference and correct your code.

Filter DataGridView using ComboBox in Windows Forms Application using C# and VB.Net

By refering the above article i have created the example.

Code

C#

private void Form1_Load(object sender, EventArgs e)
{
    // Populate DataGridView.
    dataGridView1.DataSource = GetData("");
    // Populate TreeViewNode.
    TreeNode node = new TreeNode("UK");
    treeView1.Nodes.Add(node);
    node = new TreeNode("USA");
    treeView1.Nodes.Add(node);
    node = new TreeNode("Canada");
    treeView1.Nodes.Add(node);
}

private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
    if (treeView1.SelectedNode != null)
    {
        textBox1.Text = treeView1.SelectedNode.Text;
    }
    dataGridView1.DataSource = GetData(treeView1.SelectedNode.Text);
}

private DataTable GetData(string country)
{
    string query = "SELECT CustomerID, ContactName, Country FROM Customers";
    query += " WHERE Country = @Country";
    query += " OR ISNULL(@Country, '') = ''";
    string constr = @"Data Source=.;Initial Catalog=Northwind;User ID=sa;Password=pass@123";
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            cmd.Parameters.AddWithValue("@Country", country);
            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 = GetData("")
    Dim node As TreeNode = New TreeNode("UK")
    treeView1.Nodes.Add(node)
    node = New TreeNode("USA")
    treeView1.Nodes.Add(node)
    node = New TreeNode("Canada")
    treeView1.Nodes.Add(node)
End Sub

Private Sub treeView1_AfterSelect(ByVal sender As Object, ByVal e As TreeViewEventArgs)
    If treeView1.SelectedNode IsNot Nothing Then
        textBox1.Text = treeView1.SelectedNode.Text
    End If

    dataGridView1.DataSource = GetData(treeView1.SelectedNode.Text)
End Sub

Private Function GetData(ByVal country As String) As DataTable
    Dim query As String = "SELECT CustomerID, ContactName, Country FROM Customers"
    query += " WHERE Country = @Country"
    query += " OR ISNULL(@Country, '') = ''"
    Dim constr As String = "Data Source=.;Initial Catalog=Northwind;User ID=sa;Password=pass@123"
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(query, con)
            cmd.Parameters.AddWithValue("@Country", country)
            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