Database search on key press

Question

I want my DataGridView filters data as I type.

    private void textSearch_TextChanged(object sender, EventArgs e)
    {
        Console.WriteLine("text_search_TextChanged()");

        LoadToDataGridView();            

        filterTextBox.Focus();
    } 

This code is painfully slow. It halts at each character as I type.

What can I do to improve the speed?

.

Source code

    void LoadToDataGridView()
    {
        Console.WriteLine("LoadToDataGridView()...");

        dataGridView1.Rows.Clear();

        IList<Word> items = null;

        string like = filterTextBox.Text;

        if (groupCheckBox.Checked || learntCheckBox.Checked)
        {
            LearntTypeEnum learntType = (LearntTypeEnum)learntComboBox.SelectedIndex;
            int groupNo = (int)groupComboBox.Items[groupComboBox.SelectedIndex];
            int correctness = InMemoryValues.CorrectnessRepetition;

            if(groupCheckBox.Checked && learntCheckBox.Checked)
            {
                if (learntType == LearntTypeEnum.All)//all
                {
                    items = _wordDatabase.GetByGroup(groupNo);//, like);
                }
                else if (learntType == LearntTypeEnum.NotLearnt)//not learnt
                {
                    items = _wordDatabase.GetByCorrectnessBelow(groupNo, correctness);//, like);
                }
                else//learnt
                {
                    items = _wordDatabase.GetByCorrectnessBeyond(groupNo, correctness);//, like);
                }
            }
            else if (groupCheckBox.Checked)
            {
                items = _wordDatabase.GetByGroup(groupNo);//, like);
            }
            else // if(learntCheckBox.Checked)
            {
                if (learntType == LearntTypeEnum.All)//all
                {
                    items = _wordDatabase.Get();//ByLike(like);
                }
                else if (learntType == LearntTypeEnum.NotLearnt)//not learnt
                {
                    items = _wordDatabase.GetByCorrectnessBelow(correctness);//, like);
                }
                else//learnt
                {
                    items = _wordDatabase.GetByCorrectnessBeyond(correctness);//, like);
                }
            }
        }
        else
        {
            items = _wordDatabase.Get();
        }

        if (items != null)
        {
            if (items.Count > 0)
            {
                Console.WriteLine(items[0].Name);

                int i = 0;
                foreach (Word c in items)
                {
                    dataGridView1.Rows.Add((c.CorrectnessCount==InMemoryValues.CorrectnessRepetition)?true:false
                        ,c.GroupNo, c.Name, c.CorrectnessCount, c.Meaning);
                    dataGridView1.Rows[i].Tag = c;
                    ++i;
                }

                IList<Word> likes = _wordDatabase.GetByLike(like);

                if(likes != null)
                {
                    if(likes.Count > 0)
                    {
                        Word word = likes[0];

                        SetFocusToWord(word);
                    }
                }

                totalRowsLabel.Text = items.Count.ToString();
            }
            else
            {
                totalRowsLabel.Text = "0";
            }
        }
        else
        {
            totalRowsLabel.Text = "0";
        }
    }