How to filter GridView records based on TextBox on Button click using C# and VB.Net in ASP.Net

Hi Ruben12345,

I have created sample code which fulfill your requirement.

HTML

<form id="form1" runat="server">
Search Customer:
<asp:TextBox ID="txtSearch" runat="server"></asp:TextBox>
<asp:Button ID="btnSearch" runat="server" Text="Search" OnClick="btnSearch_Click" />
<hr />
<asp:GridView ID="GridView1" HeaderStyle-BackColor="#3AC0F2" HeaderStyle-ForeColor="White"
    runat="server" PageSize="10" AutoGenerateColumns="false" AllowPaging="true">
    <Columns>
        <asp:BoundField DataField="ContactName" HeaderText="Name" ItemStyle-Width="150" />
        <asp:BoundField DataField="City" HeaderText="City" ItemStyle-Width="150" />
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150" />
    </Columns>
</asp:GridView>
</form>

C#

String strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
protected void Page_load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        this.GetData();
    }
}

private void GetData()
{
    SqlConnection con = new SqlConnection(strConnString);
    SqlCommand cmd = new SqlCommand("SELECT  * FROM Customers", con);
    SqlDataAdapter sda = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    sda.Fill(dt);
    GridView1.DataSource = dt;
    GridView1.DataBind();
}

protected void btnSearch_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection(strConnString);
    SqlCommand cmd = new SqlCommand("SELECT  * FROM Customers  where ContactName like @contactName + '%'", con);
    cmd.Parameters.AddWithValue("@contactName", txtSearch.Text.Trim());
    SqlDataAdapter sda = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    sda.Fill(dt);
    GridView1.DataSource = dt;
    GridView1.DataBind();
}

Vb.net

Private strConnString As [String] = ConfigurationManager.ConnectionStrings("conString").ConnectionString
Protected Sub Page_load(sender As Object, e As EventArgs)
	If Not IsPostBack Then
		Me.GetData()
	End If
End Sub

Private Sub GetData()
	Dim con As New SqlConnection(strConnString)
	Dim cmd As New SqlCommand("SELECT  * FROM Customers", con)
	Dim sda As New SqlDataAdapter(cmd)
	Dim dt As New DataTable()
	sda.Fill(dt)
	GridView1.DataSource = dt
	GridView1.DataBind()
End Sub

Protected Sub btnSearch_Click(sender As Object, e As EventArgs)
	Dim con As New SqlConnection(strConnString)
	Dim cmd As New SqlCommand("SELECT  * FROM Customers  where ContactName like @contactName + '%'", con)
	cmd.Parameters.AddWithValue("@contactName", txtSearch.Text.Trim())
	Dim sda As New SqlDataAdapter(cmd)
	Dim dt As New DataTable()
	sda.Fill(dt)
	GridView1.DataSource = dt
	GridView1.DataBind()
End Sub

Screenshot