Problem with Search DataGridView by using ComboBox and Text

Question

Good morning all,

I try to affect a filter / search on datagridview by a combobox and textbox but when I type the first letter (s) on textbox an error message is displayed:

System.Data.SqlClient.SqlException*: 'Syntaxe incorrect vers 's%'.'

here is my code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Configuration;
using System.Data.SqlClient;

namespace TESTSEARCH
{
public partial class FormFind : Form
{
public FormFind()
{
InitializeComponent();
}
private void FormFind_Load(object sender, EventArgs e)
{
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
string constring = ConfigurationManager.ConnectionStrings["TESTDEMO.Properties.Settings.connect"].ConnectionString;
SqlConnection con = new SqlConnection(constring);
if (comboBox1.Text == "BD_NameConn")
{
SqlDataAdapter Sda = new SqlDataAdapter ("Select BD_NameConn, BD_BaseType, BD_Base, BD_Serer, BD_User, BD_MenuStyle FROM BD WHERE BD_NameConn '" + textBox1.Text + "%'",con);
DataTable Dt = new DataTable();
Sda.Fill(Dt);
dataGridView1.DataSource = Dt;
}
}
}
}

it stops in the line Sda.Fill (Dt); and displays the message :

System.Data.SqlClient.SqlException*: 'Syntaxe incorrecte vers 's%'.'

I await your help and thank you in advance