Help C# SQL error near '='

A few problems with the code; a vulnerability, your actual problem, an inefficiency, and some notes/suggestions for you.

1. Concatenated strings should never be used, this is a SQL Injection vulnerability; it's been known for over 20 years now and is unacceptable. Use SqlParamaters to add the values to the command object.

2. Items in the SET list should be separated with a comma(,)- not an ampsersand (&).

3. The SqlDataAdapter is designed for working with data retrieval, and has an overhead to it which is not needed for this application. All you need to run this is a SqlCommand object.

4. ExecuteNonQuery returns an Int32 to let you know how many rows were affected. You can use this to verify the query was run as expected. I threw it into your message box.

5. You should be using try/catch blocks which I added in. Ideally this should all be wrapped in a using block to properly dispose of the resources.

enuff of that... here is the code rewrite that I did

using (SqlConnection con = new SqlConnection(connectionsting)) {
  try {
    string query = "UPDATE Emp2 SET DateOut = @Dateout, TimeOut = @Timeout WHERE No = @No";
    SqlCommand cmd = new SqlCommand(query, con);
    cmd.Parameters.AddWithValue("@Dateout", textBox11.Text);
    cmd.Parameters.AddWithValue("@Timeout", textBox5.Text);
    cmd.Parameters.AddWithValue("@No", textBox1.Text);

    con.Open();
    int RowsAffected = cmd.ExecuteNonQuery();
    con.Close();

    MessageBox.Show(string.Format("UPDATE SUCCESS! {0} rows were updated". RowsAffected));
  }
  catch (Exception ex) { 
    // your error handling code
  }
}

You don't need to use & operator in update query, Just replace it with ,

Update your SQL query as below.

string query = "UPDATE Emp2 SET DateOut ='" + textBox11.Text + "', TimeOut ='" + textBox5.Text + "' WHERE No = '" + textBox1.Text + "'";

for best practices, Don't use inline queries, It leads to SQL injection which is a major security hole for your application.