Question

我希望能够对我的代码中缺少的内容有所了解我有一个文本框绑定到一个对象属性，该属性是列表中的项目，如果我请求列表中的另一个项目，该值不会在表单上更新。

举例说明如下：
在openJSONRequestFileToolStripMenuItem_Click功能后填充txtGain值一旦我在cmbSignals组合框中选择了不同的东西，我预计txtGain值会随着SelectedChannel的更新而更新，这反过来会更新selectedindex，但它不会发生。

基本上我想根据我在cmbSignals中选择的内容更新我的txtGain值。显然绑定是存在的，所以我可以修改文本框中的值，并在它绑定的属性中更新它。

我怀疑我必须以某种方式强制更新绑定但不知道如何做到这一点。任何帮助将不胜感激。

public partial class MainForm : Form
{
    private MyData req;  

    public MainForm()
    {
        InitializeComponent();

        cmbSignals.DisplayMember = "Name";
        cmbSignals.ValueMember = "Value";
    }

    private void openJSONRequestFileToolStripMenuItem_Click(object sender, EventArgs e)  
    {
        string text = File.ReadAllText("sample.json");    
        req = new MyData(JsonConvert.DeserializeObject<SerializedRequest>(text));  
        cmbSignals.DataSource = req.SignalNames;  
        cmbSignals.SelectedValue = req.SelectedChannel;     
        SetBindings();
    }

    private void SetBindings()
    {
        txtGain.DataBindings.Add(new Binding("Text", req, "Gain"));
    }

    private void cmbSignals_SelectedValueChanged(object sender, EventArgs e)
    {
        req.SelectedChannel = Convert.ToInt32(cmbSignals.SelectedValue);
    }
}




public class MyData : INotifyPropertyChanged
{
    private SerializedRequest Data = new SerializedRequest();
    private int selectedIndex = 0;

    public int SelectedChannel
    {
        get
        {
            return selectedIndex + 1;
        }
        set
        {
            this.selectedIndex = value - 1;
        }
    }

    public string Gain
    {
        get
        {
            return Data.signals[selectedIndex].gain;
        }
        set
        {
            Data.signals[selectedIndex].gain = value;
            OnPropertyChanged("Gain");
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }

    public List<SignalsCmbItem>SignalNames
    {

        get
        {
            List<SignalsCmbItem>channels = new List<SignalsCmbItem>();
            for(int i = 0; i<Data.signals.Count;i++)
            {
                channels.Add(new SignalsCmbItem { Value = i + 1, Name = i+1 + " - " + Data.signals[i].label });
            }
            return channels;
        }
    }
}

Answer 1

非常讨厌＆＃34;功能＆＃34;，不是吗？

但不用担心，为了解决这个问题，在更改cmbSignals_SelectedValueChanged(sender, e)的值后，在req.SelectedChannel方法中添加一行代码。

txtGain.BindingContext = new BindingContext();

Winforms双向数据绑定：强制更新字段

1 个答案: