C# email 地址 combobox

Question

我有一個 combobox ，其中包含郵件收件人的地址。 當它被下拉時，用戶會看到他曾經發送過郵件的所有地址的列表。 我希望 combobox 到 append 地址在它的文本字段中，而不是替換那里的所有文本。

So for example, I have a list of emails aaa@mail.com, bbb@mail.com, ccc@mail.com in combobox's list and aaa@mail.com is in combobox.Text. When I select bbb@mail.com from cbox's list I want to combobox.Text to became "aaa@mail.com, bbb@mail.com" but Text just becames bbb@mail.com.

This is the combobox:
+----------------+                                     +----------------+
| aaa@mail.com |V|                                     | aaa@mail.com |V|
+----------------+                                     +----------------+
| aaa@mail.com   |                                     | aaa@mail.com   |
| bbb@mail.com   |    trying to select this brings     | bbb@mail.com   | 
| ccc@mail.com   |       which is not desired          | ccc@mail.com   |
+----------------+                                     +----------------+

When someone clicks on aaa@mail.com or bbb@mail.com or ccc@mail.com the editable field becomes that value. For example, after selecting bbb@mail.com it will become 
+----------------+
| bbb@mail.com |V|
+----------------+

I want combobox to append values and not just select them. So I want it to show
+------------------------------+
| aaa@mail.com, bbb@mail.com |V|
+------------------------------+

instead of just 
+----------------+
| bbb@mail.com |V|
+----------------+

我寫了這段代碼（它只是一個帶有 combobox 的表單，按鈕和按鈕，設置了表單的 FormClosed 事件，設置了按鈕的 Click 事件，並設置了組合框的事件 selectedIndexChanged 和 TextChanged）但它不像我預期的那樣工作。

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        cboxFrom.Tag = string.IsNullOrEmpty(Settings.Default.emailFrom) ? "" : Settings.Default.emailFrom;
        cboxFrom.Text = (string)cboxFrom.Tag;
        if (Settings.Default.emailFroms == null)
            Settings.Default.emailFroms = new System.Collections.Specialized.StringCollection();
        //cboxFrom.DataSource = Settings.Default.emailFroms;
        foreach (string s in Settings.Default.emailFroms)
        cboxFrom.Items.Add(s);
    }

    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        Settings.Default.Save();
    }

    private void cboxFrom_SelectedIndexChanged(object sender, EventArgs e)
    {
        try
        {
            ComboBox cbox = (ComboBox)sender;
            string addr = (string)cbox.Items[cbox.SelectedIndex];
            if (addr != null && cbox.Tag != null && !(cbox.Tag as string).Contains(addr))
            {
                if (cbox.Text.Trim().Length == 0)
                    cbox.Text = addr;
                else
                    cbox.Text = cbox.Tag + ", " + addr;
                cbox.Tag = cbox.Text;
            }
            else
                cbox.Text = (string)cbox.Tag;
        }
        catch { }
    }

    private void cboxFrom_KeyPress(object sender, KeyPressEventArgs e)
    {
        ComboBox cbox = (ComboBox)sender;
        cbox.Tag = cbox.Text;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        string[] addrs = cboxFrom.Text.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
        foreach(string s in addrs)
        if(!Settings.Default.emailFroms.Contains(s.Trim()))
            Settings.Default.emailFroms.Add(s);
    }
}

Answer 1

我這里只有一個建議。

而不是附加您的 comboBox 文本。 為什么不添加一個文本框和另一個按鈕，單擊時將 comboBox 中的選定 email 地址添加到文本框？ 添加 textBox.Text 屬性會更簡單，它還允許用戶在將其添加到發送列表之前確保他選擇了正確的 email。

據我了解，按照您的方式進行操作有很多 email，向下滾動用戶可能會做出錯誤的選擇，然后它會自動添加到您的 comboBox.Text 中，用戶無法退出。