更新ListBox的背景色

本文关键字：背景色 ListBox 更新 | 更新日期: 2023-09-27 18:12:15

我需要更新我的ListBox的BackColor通过选择从组合框的颜色，当点击按钮。这是我的代码

      public Data _current;
    public Data Current
    {
        get
        { return _current; }
        set
        {
            _current = value;
            if (PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs("Current"));
            }
        }
    }
    public Form1()
    {
        InitializeComponent();
        Items = new ObservableCollection<Data>();
        for (int i = 0; i < names.Count; i++)
        {
            Items.Add(new Data() {Name=names[i].ToString().TrimStart(new char[] { '[', 'C', 'o', 'l', 'o', 'r', ' ', ']' }).TrimEnd(new char[] { ']' }), color = names[i] });
        }
        comboBox1.DataSource = Items;
        comboBox1.DisplayMember ="Name";
        Current = Items.First();
    }
    public List<Color> names = new List<Color>() { Color.Red,Color.Yellow,Color.Green,Color.Blue };
    public event PropertyChangedEventHandler PropertyChanged;
    private void button1_Click(object sender, EventArgs e)
    {
        Current = comboBox1.SelectedItem as Data;
        listBox1.DataBindings.Add("BackColor", Current, "color", true, DataSourceUpdateMode.OnPropertyChanged);
    }
    private void Form1_Load(object sender, EventArgs e)
    {
    }
}
public class Data:INotifyPropertyChanged
{
    private Color _color;
    public string name { get; set; }
    public string Name
    {
        get
        { return name; }
        set
        {
            name = value;
            if (PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs("Name"));
            }
        }
    }
    public Color color
    {
        get
        {
            return _color;
        }
        set
        {
            _color = value;
            if (PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs("color"));
            }
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;
}

异常弹出并说:"这会导致集合中的两个绑定绑定到同一属性。"

更新ListBox的背景色

为了解决你原来的问题"我需要更新我的ListBox的背景颜色从组合框中选择的颜色，当点击按钮"，你不需要数据绑定在所有。你可以直接用

private void button1_Click( object sender, EventArgs e )
{
    listBox1.BackColor = (Color)comboBox1.SelectedValue;
}

如果你真的想用数据绑定来做，你可以直接在列表框和组合框之间绑定(好吧，这不需要点击按钮):

listBox1.DataBindings.Add( "BackColor", comboBox1, "SelectedValue", true, DataSourceUpdateMode.OnPropertyChanged );

如果你需要数据绑定和按钮点击，你可以绑定组合框与表单。当前

comboBox1.DataBindings.Add( "SelectedItem", this, "Current", true, DataSourceUpdateMode.OnPropertyChanged );

和更新背景色按钮点击:

private void button1_Click( object sender, EventArgs e )
{
    listBox1.BackColor = Current.Color;
}

下面是完整的示例，包括一些改进:

public class Data : INotifyPropertyChanged
{
    public string Name
    {
        get { return color.Name; }
    }
    private Color color;
    public Color Color
    {
        get { return color; }
        set
        {
            color = value;
            if( PropertyChanged != null )
                this.PropertyChanged( this, new PropertyChangedEventArgs( "Color" ) );
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;
}
public class Form1 : Form
{
    private ComboBox comboBox1;
    private ListBox listBox1;
    private Button button1;
    public Form1()
    {
        InitializeComponent();
        List<Data> dataList = new List<Data>
        {
            new Data { Color = Color.Red },
            new Data { Color = Color.Yellow },
            new Data { Color = Color.Green },
            new Data { Color = Color.Blue },
        };
        comboBox1.DataSource = dataList;
        comboBox1.DisplayMember = "Name";
        comboBox1.ValueMember = "Color";
    }
    public Data Current
    {
        get { return comboBox1.SelectedItem as Data; }
    }
    private void button1_Click( object sender, EventArgs e )
    {
        listBox1.BackColor = Current.Color;
    }
    private void InitializeComponent()
    {
        //...
    }
}

您只能绑定一次控件的任何属性，否则您将收到ArgumentException:

这会导致集合中的两个绑定绑定到相同的绑定财产。参数名称:binding

在你的代码中，你在按钮的点击事件处理程序中添加了数据绑定，每次点击代码都执行。

要解决这个问题，将数据绑定代码移动到Load事件的表单。

如果出于任何原因你想在click event of button中添加绑定，为了解决这个问题，你可以检查绑定是否没有添加，然后添加绑定:

if (listBox1.DataBindings["BackColor"] == null)
    listBox1.DataBindings.Add("BackColor", Current, "color", true, 
        DataSourceUpdateMode.OnPropertyChanged);
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