how to fix this code ?

You have a try with no catch or finally. It's right after Clear();, you have a closing brace and then an opening one.

Just to add to what RyanDev correctly identified: If you get a problem like this, put your cursor on the open curly bracket after the try and press CTRL+] - it will move to the "Matching" bracket (even if they are wrong) so you can see where the compiler thinks it is.

One more thing you need to fix: Always use parameters in your SQL statements instead of concatenating text directly to you SQL text. This helps you to handle different data type conversions etc but most importantly, it keeps you safe from SQL injections

For example your update currently looks like

CN.Open();

SqlStr = "Update  Student set ";
SqlStr = SqlStr + " Name='"+TxtName.Text+"' , ";
SqlStr = SqlStr + " Director='" +  TxtDirector.Text + "' , ";
SqlStr = SqlStr + " Year='" +  TxtYear.Text + "' , ";
SqlStr = SqlStr + " Type='" +  TxtType. Text + "' , ";
SqlStr = SqlStr + " where Id_Movies='" + TxtID.Text + "'  ";

SqlCmd = new SqlCommand(SqlStr, CN);
SqlCmd.ExecuteNonQuery();

MessageBox.Show("Edited successfully.");
Clear();

As said you should use parameters so the code should be something like

CN.Open();

SqlStr = @"UPDATE Student 
SET Name     = @name,
    Director = @director,
    Year     = @year,
    Type     = @type,
WHERE Id_Movies = @id";

SqlCmd = new SqlCommand(SqlStr, CN);
SqlCmd.Parameters.AddWithValue("@name", TxtName.Text);
SqlCmd.Parameters.AddWithValue("@director", TxtDirector.Text);
SqlCmd.Parameters.AddWithValue("@year", TxtYear.Text);
SqlCmd.Parameters.AddWithValue("@type", TxtType. Text);
SqlCmd.Parameters.AddWithValue("@id", TxtID.Text);
SqlCmd.ExecuteNonQuery();

MessageBox.Show("Edited successfully.");
Clear();

Of course it would make sense to first check that the inputs in the text boxes are valid. FOr example TxtID being numeric if that is the type of the field and so on.

For more information about parameters, see SqlParameter[^]

This compiles just fine, however the "Clean()" method isnt included in your code so I just commented it out.

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

namespace movies
{
    public partial class Form1 : Form
    {
        string SqlStr;
        SqlCommand SqlCmd;
        SqlDataAdapter SqlDa;
        SqlDataReader SqlDr;
        SqlConnection CN = new SqlConnection("Data Source=(local);Initial Catalog=Movies;Integrated Security=True");

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 form2 = new Form2();
            form2.Show();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            try
            {
                CN.Open();

                SqlStr = "Insert into Student( [Name]";
                SqlStr = SqlStr + " ,[Director]";
                SqlStr = SqlStr + " ,[Year]";
                SqlStr = SqlStr + " ,[Type]";
                SqlStr = SqlStr + " Values('" + TxtName.Text + "','" + TxtDirector.Text + "',";
                SqlStr = SqlStr + "'" + TxtYear.Text + "'  ,";
                SqlStr = SqlStr + "'" + TxtType.Text + "',";
                SqlCmd = new SqlCommand(SqlStr, CN);
                SqlCmd.ExecuteNonQuery();

                MessageBox.Show("successfully added.");
                // Clear(); Not sure what this is?
            }
            catch (Exception) { }

            {
                try
                {
                    CN.Open();

                    SqlStr = "   select Name,Director,Year,Type ";
                    SqlStr = SqlStr + " from Movies";
                    SqlStr = SqlStr + " where Id_Movies='" + lab4.Text + "'  ";

                    SqlCmd = new SqlCommand(SqlStr, CN);
                    SqlDr = SqlCmd.ExecuteReader();

                    SqlDr.Read();

                    if (!SqlDr.HasRows)
                    {
                        MessageBox.Show("found nothing.");
                    }
                    else
                    {
                        TxtName.Text = SqlDr["Name"].ToString();
                        TxtDirector.Text = SqlDr["Director"].ToString();
                        TxtYear.Text = SqlDr["Year"].ToString();
                        TxtType.Text = SqlDr["Type"].ToString();

                    }

                }

                finally
                {
                    CN.Close();
                }
            }
            {
                try
                {

                    CN.Open();

                    SqlStr = "Update  Student set ";
                    SqlStr = SqlStr + " Name='" + TxtName.Text + "' , ";
                    SqlStr = SqlStr + " Director='" + TxtDirector.Text + "' , ";
                    SqlStr = SqlStr + " Year='" + TxtYear.Text + "' , ";
                    SqlStr = SqlStr + " Type='" + TxtType.Text + "' , ";
                    SqlStr = SqlStr + " where Id_Movies='" + TxtID.Text + "'  ";

                    SqlCmd = new SqlCommand(SqlStr, CN);
                    SqlCmd.ExecuteNonQuery();

                    MessageBox.Show("Edited successfully.");
                    // Clear(); Not sure what this is?	 
                }
                finally
                {
                    CN.Close();
                }
            }
        }
    }
}