在c＃中添加项目并在windows窗体上展开checkedlistbox的集合列表时出现问题

This may seem like a dumb question. I have a textbox that can be used to add items to a checkedlistbox at runtime on a windows form. I'm using c#. It works perfectly fine at runtime. The item gets added and stuff, when the form is open. But, when I close and open the form again, I don't see the added item in the checkedlistbox list. Note, I don't use a datasource and don't want to. I wouldn't want to hardcode anything and would prefer to use a textbox input on the form as a variable to feed into the collections list. I couldn't figure out a way to expand my checkedlistbox options. Any assistance would be appreciated.

这似乎是一个愚蠢的问题。我有一个文本框,可用于在Windows窗体上运行时将项目添加到checkedlistbox。我正在使用c#。它在运行时完美运行。当表单打开时,项目会被添加和填充。但是,当我再次关闭并打开表单时,我没有在checkedlistbox列表中看到添加的项目。注意,我不使用数据源而不想。我不想硬编码任何东西,并且更喜欢使用表单上的文本框输入作为变量来输入集合列表。我无法找到扩展我的checkedlistbox选项的方法。任何援助将不胜感激。

3 个解决方案

#1

How are you opening the form? Is it something like:

你是如何打开表格的?是这样的:

FormName form = new FormName();
form.Show()

The only reason I can think that's happening is that you're instantiating a new form instance every time you show it, instead of reusing the same form.

我认为发生这种情况的唯一原因是,每次显示时都会实例化一个新的表单实例,而不是重复使用相同的表单。

#2

Have your Form take a ref List<string> values as parameter. Then make this as BindingSource for the CheckedListBox.

让您的表单将ref List 值作为参数。然后将其作为CheckedListBox的BindingSource。

Here is the code:

这是代码:

class MyForm : Form {
        List<string> values;
        BindingSource source;

        public MyForm()
        {
            InitializeComponent();
        }

        public MyForm(ref List<string> values):this()
        {
            if (values == null)
                values = new List<string>();

            this.values = values;

            checkedListBox1.DisplayMember = "Value";
            checkedListBox1.ValueMember = "Value";
            source = new BindingSource(this.values, null);
            checkedListBox1.DataSource = source;
        }

        private void AddItemButton_Click(object sender, EventArgs e)
        {
            this.source.Add(textBox1.Text);
            textBox1.Text = string.Empty;
        }
}

#3

private void frmMain_Load(object sender, EventArgs e)
{
  if (!string.IsNullOrEmpty(Properties.Settings.Default.CheckedItems))
  {
    string[] checkedIndicies = Properties.Settings.Default.CheckedItems.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
    for (int i1 = 0; i1 < checkedIndicies.Length; i1++)
    {
      int idx;
      if ((int.TryParse(checkedIndicies[i1], out idx)) && (checkedListBox1.Items.Count >= (idx+1)))
      {
        checkedListBox1.SetItemChecked(idx, true);
      }
    }
  }
}

private void button2_Click(object sender, EventArgs e)
    {
        if (textBox1.Text != "")
        {
            textBox1.MaxLength = 15;
            // Change all text entered to be lowercase.
            textBox1.CharacterCasing = CharacterCasing.Lower;

            if (checkedListBox1.Items.Contains(textBox1.Text) == false)
            {
                checkedListBox1.Items.Add(textBox1.Text, CheckState.Checked);

                textBox1.Text = "";
                MessageBox.Show("Added! Click Move to see List Box");
            }

            else
            {
                MessageBox.Show("Already There!");
                textBox1.Text = "";
            }
        }
    }



private void frmMain_FormClosing(object sender, FormClosingEventArgs e)
{
  string idx = string.Empty;
  for (int i1 = 0; i1 < checkedListBox1.CheckedIndices.Count; i1++)
    idx += (string.IsNullOrEmpty(idx) ? string.Empty : ",") + Convert.ToString(checkedListBox1.CheckedIndices[i1]);
  Properties.Settings.Default.CheckedItems = idx;
  Properties.Settings.Default.Save();
}

#1