c# - 在 C# Windows 窗体中使用文本搜索过滤组合框项目

Question

我试图在项目的所有字符中使用其文本属性来过滤组合框，而不仅仅是它们的开头。我在我的组合框的 TextChanged 事件中尝试下面的代码。但不幸的是，组合框在输入任何键后重置:

    private void cmbCompany_TextChanged(object sender, EventArgs e)
    {
        string QueryCompany = string.Format("select id,title from acc.dl where title LIKE '%" + cmbCompany.Text + "%' union select null , null order by title");
        SqlDataAdapter DA1 = new SqlDataAdapter(QueryCompany, con);
        DataTable DT1 = new DataTable();
        DA1.Fill(DT1);
        cmbCompany.DisplayMember = "Title";
        cmbCompany.ValueMember = "id";
        cmbCompany.DataSource = DT1;
    }

连接字符串“con”已定义并打开。感谢您的帮助。

Answer 1

下面是对我有用的代码部分，其中搜索部分不仅在开头而且在中间都有效。我还粘贴了额外的部分，负责在您按下回车按钮后将焦点移动到表单上的下一个控件。

初始化部分:

public Form1()
{
  InitializeComponent();

  cmbItems = new List<ComboBoxItem>();
  InitializeComboBox();

}

private void InitializeComboBox()
{
  Random rand = new Random();
  for (int i = 0; i <= 1500; i++)
  {
    int counter = rand.Next(1, 105000);
    cmbItems.Add(new ComboBoxItem("randomNumber" + counter, "ID_" + counter));
  }
  comboBox1.DataSource = cmbItems;
}

过滤部分:

private void comboBox1_TextUpdate(object sender, EventArgs e)
{

  if (comboBox1.Text == string.Empty)
  {
    comboBox1.DataSource = cmbItems; // cmbItems is a List of ComboBoxItem with some random numbers
    comboBox1.SelectedIndex = -1;
  }
  else
  {
    string tempStr = comboBox1.Text;
    IEnumerable<ComboBoxItem> data = (from m in cmbItems where m.Label.ToLower().Contains(tempStr.ToLower()) select m);

    comboBox1.DataSource = null;
    comboBox1.Items.Clear();

    foreach (var temp in data)
    {
      comboBox1.Items.Add(temp);
    }
    comboBox1.DroppedDown = true;
    Cursor.Current = Cursors.Default;
    comboBox1.SelectedIndex = -1;

    comboBox1.Text = tempStr;
    comboBox1.Select(comboBox1.Text.Length, 0);

  }
}

移动焦点部分:

private void comboBox1_KeyPress(object sender, KeyPressEventArgs e)
{
  if (e.KeyChar != '\r') return;

  if (this.ActiveControl != null)
  {
    this.SelectNextControl(this.ActiveControl, true, true, true, true);
  }
  e.Handled = true; // Mark the event as handled
}

希望对大家有所帮助。