您必须创建自己的类类型并重写ToString()方法以返回所需的文本。下面是一个你可以使用的类的简单例子:

public class ComboboxItem
{
    public string Text { get; set; }
    public object Value { get; set; }

    public override string ToString()
    {
        return Text;
    }
}

下面是它使用的一个简单例子:

private void Test()
{
    ComboboxItem item = new ComboboxItem();
    item.Text = "Item text1";
    item.Value = 12;

    comboBox1.Items.Add(item);

    comboBox1.SelectedIndex = 0;

    MessageBox.Show((comboBox1.SelectedItem as ComboboxItem).Value.ToString());
}

// Bind combobox to dictionary
Dictionary<string, string>test = new Dictionary<string, string>();
        test.Add("1", "dfdfdf");
        test.Add("2", "dfdfdf");
        test.Add("3", "dfdfdf");
        comboBox1.DataSource = new BindingSource(test, null);
        comboBox1.DisplayMember = "Value";
        comboBox1.ValueMember = "Key";

// Get combobox selection (in handler)
string value = ((KeyValuePair<string, string>)comboBox1.SelectedItem).Value;

Visual Studio 2013是这样做的:

单一项目:

comboBox1->Items->AddRange(gcnew cli::array< System::Object^  >(1) { L"Combo Item 1" });

多个项目:

comboBox1->Items->AddRange(gcnew cli::array< System::Object^  >(3)
{
    L"Combo Item 1",
    L"Combo Item 2",
    L"Combo Item 3"
});

不需要重写类或包含任何其他内容。是的，comboBox1->SelectedItem和comboBox1->SelectedIndex调用仍然有效。

这里有更好的解决方案;

Dictionary<int, string> userListDictionary = new Dictionary<int, string>();
        foreach (var user in users)
        {
            userListDictionary.Add(user.Id,user.Name);
        }

        cmbUser.DataSource = new BindingSource(userListDictionary, null);
        cmbUser.DisplayMember = "Value";
        cmbUser.ValueMember = "Key";

检索数据

MessageBox.Show(cmbUser.SelectedValue.ToString());

这是我想到的方法之一:

combo1.Items。添加(new ListItem("Text"， "Value"))

要更改一个项目的文本或值，你可以这样做:

combo1.Items[0].Text = 'new Text';

combo1.Items[0].Value = 'new Value';

在Windows窗体中没有名为ListItem的类。它只存在于ASP中。因此，在使用它之前，您需要编写自己的类，就像@Adam Markowitz在他的回答中所做的一样。

还可以查看这些页面，它们可能会有帮助:

如何将项目添加到组合框 如何:从Windows窗体组合框、列表框或checkkedlistbox控件中添加和删除项

using (SqlConnection con = new SqlConnection(insertClass.dbPath))
{
    con.Open();
    using (SqlDataAdapter sda = new SqlDataAdapter(
    "SELECT CategoryID, Category FROM Category WHERE Status='Active' ", con))
    {
        //Fill the DataTable with records from Table.
        DataTable dt = new DataTable();
        sda.Fill(dt);
        //Insert the Default Item to DataTable.
        DataRow row = dt.NewRow();
        row[0] = 0;
        row[1] = "(Selecione)";
        dt.Rows.InsertAt(row, 0);
        //Assign DataTable as DataSource.
        cboProductTypeName.DataSource = dt;
        cboProductTypeName.DisplayMember = "Category";
        cboProductTypeName.ValueMember = "CategoryID";
    }
}             
con.Close();