Autocomplete textbox with backgroundworker C#

Question

5.00/5 (1 vote)

See more:

Please, I have created a winforms in C# and I want to use backgroundWorker to retrieve data from the database. This code works without using backgroundWorker and it makes the winForms slow once I tried to put the code under Form_Load.

Please any help would be appreciated.....

What I have tried:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {      
            try
            {
                con.Open();
                cmd = new MySqlCommand(@"SELECT CONCAT(fname,' ',lname,' ',oname) as name, phoneno FROM dbchurch.member WHERE status = 1;", con);
                reader = cmd.ExecuteReader();
                AutoCompleteStringCollection list_of_member = new AutoCompleteStringCollection();
                while (reader.Read())
                {
                    list_of_member.Add(string.Format("{0}", reader["name"]));
                    list_of_member.Add(string.Format("{0}", reader["phoneno"]));
                }
                backgroundWorker1.ReportProgress(0, list_of_member);
                reader.Close();
                con.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(string.Format("An error occurred {0}", ex.Message), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            finally
            {
                reader.Dispose();
                con.Dispose();
            }
        }

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            AutoCompleteStringCollection list_of_member = (AutoCompleteStringCollection)e.UserState;
            txtsearch.AutoCompleteCustomSource.AddRange(e.UserState);
        }

Posted 18-Feb-22 3:55am

Member 12887106

Updated 18-Feb-22 4:10am

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2022-02-18T04:10:00

First off, I wouldn't use Progress reporting for that - I'd use that to add each item as it was processed, not the whole lot at once.
For a "single action" I'd handle the RunWorkerCompleted Event[^] instead as it's more obvious when is happening.

But your progress handling code doesn't help you at all:

AutoCompleteStringCollection list_of_member = (AutoCompleteStringCollection)e.UserState;
txtsearch.AutoCompleteCustomSource.AddRange(e.UserState);

Why cast the UserState to a useful type if all you do is ignore it and use the original object variable to set the range?
Since there isn't an AddRange overload that takes an object parameter, that probably doesn't even compile ...