Question

我刚创建了一个包含许多组合框的表单，但它们只使用相同的数据。第一次，我为radiobutton上的每次点击加载数据，但这需要一些时间，而且非常烦人。因此，每次点击一个单选按钮时，我都不想加载组合框，而是希望它在应用程序启动时只加载一次。

以下代码是创建可在表单中的任何位置调用的全局组合框。

    public partial class Form1 : Form
    {
       //code to get the requester below
       public List<XMLSoccerCOM.Team> all_team = requester.GetAllTeams();
       public List<XMLSoccerCOM.League> all_league = requester.GetAllLeagues();

       public ComboBox combo_team = new ComboBox();   //global combo_team
       public ComboBox combo_league = new ComboBox();  //global combo_league

       //the rest of the code
    }

在这个表单中，有一个init方法：

    public Form1()
    {
        InitializeComponent();
        his_combobox.Visible = false; //I hide everything so that I can show them when click on the radiobutton
        foreach (XMLSoccerCOM.Team te in all_team)    //This one for the first combobox
        {
            combo_team.Items.Add(te.Name.ToString());
        }
        foreach (XMLSoccerCOM.League le in all_league)  //And the 2nd as well
        {
           combo_league.Items.Add(le.Name.ToString());
        }
    }

所以看起来已经完成了，我只需要随时分配它。在radiobutton checkchange事件中，我做到了：

    private void history_league_CheckedChanged(object sender, EventArgs e)
    {
        his_combobox = combo_league;   // Assign the global league combobox to a local combobox.

        his_odds_label.Text = "Choose the league:"; //This label is next to the his_combobox
        his_odds_label.Visible = true;
        his_combobox.Visible = true;   //Show them if it's hidden by another radiobutton

    }

    private void history_team_CheckedChanged(object sender, EventArgs e)
    {
        his_combobox = combo_team;   // Assign the global team combobox to a local combobox.

        his_odds_label.Text = "Choose the team:"; //This label is next to the his_combobox
        his_odds_label.Visible = true;
        his_combobox.Visible = true;   //Show them if it's hidden by another radiobutton

    }

但是当我按Ctrl + F5时它没有出现，只有标签显示，his_combobox没有显示，就像它永远不会在那里一样。

随时询问更多信息。谢谢你的时间。

Answer 1

分配数据源非常重要。

his_combobox.DataSource = combo_league.DataSource;

但我会更简单地采取类似的方法。

private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        var checkbox = (CheckBox) sender;
        comboBox1.DataSource = checkbox.Checked ? all_team : all_league;
        comboBox1.Visible = true;
    }

通过这个approch你不必创建额外的组合框，但这取决于你的需要。

修改在我的例子中，我将all_team和all_league作为字符串类型，但您可以根据您的属性进行调整。

public List<String> all_team = new List<string> { "Team A", "Team B" }; public List<String> all_league = new List<string> { "League a", "League b" }; public ComboBox combo_team = new ComboBox(); //global combo_team public ComboBox combo_league = new ComboBox(); //global combo_league public Form1() { InitializeComponent(); comboBox1.Visible = false; } /// <summary> /// Method 1 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void checkBox1_CheckedChanged(object sender, EventArgs e) { var checkbox = (CheckBox) sender; comboBox1.DataSource = checkbox.Checked ? all_team : all_league; comboBox1.Visible = true; } /// <summary> /// Method2 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void checkBox2_CheckedChanged(object sender, EventArgs e) { combo_league.DataSource = all_league; combo_team.DataSource = all_team; var checkbox = (CheckBox)sender; comboBox1.DataSource = checkbox.Checked?combo_league.DataSource:combo_team.DataSource; comboBox1.Visible = true; }

Answer 2

最后，我从卡利安的一些建议中找到了答案。我创建了一个全局变量：

 public List<String> teams = new List<string>();

然后用所需的项目填写此列表（我的all_team有很多列，这就是为什么它不会出现his_combobox.DataSource = combo_team.DataSource;，因为他告诉我）

    foreach (XMLSoccerCOM.Team te in all_team)
        {
            teams.Add(te.Name.ToString());
        }

然后最终使teams数据源：

   combobox1.DataSource = teams;

全部:)谢谢。

在c＃中调用时，手动初始化的组合框不会显示

2 个答案: