我正在尝试对NumericUpDown WinForm控件执行数据绑定。执行绑定按设计工作,但是我遇到一个问题,直到元素失去焦点,该值才被推送到绑定属性。当控件中的值更改而又不需要失去焦点时,我是否缺少使属性更新的东西?
如果这按设计工作,是否有办法在不失去焦点的情况下强制更新属性?
逻辑:
using System;
using System.Windows.Forms;
public partial class Form1 : Form
{
private NumericUpDown numericUpDown1 = new NumericUpDown();
private ExampleData _ed = new ExampleData();
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
// Define the UI Control
numericUpDown1.DecimalPlaces = 7;
numericUpDown1.Location = new System.Drawing.Point(31, 33);
numericUpDown1.Name = "numericUpDown1";
numericUpDown1.Size = new System.Drawing.Size(120, 20);
numericUpDown1.TabIndex = 0;
// Add the UI Control
Controls.Add(numericUpDown1);
// Bind the property to the UI Control
numericUpDown1.DataBindings.Add("Value", _ed, nameof(_ed.SampleDecimal));
numericUpDown1.ValueChanged += NumericUpDown1_ValueChanged;
}
private void NumericUpDown1_ValueChanged(object sender, EventArgs e)
{
// This will fire as you change the control without losing focus.
System.Diagnostics.Debugger.Break();
}
}
public class ExampleData
{
public decimal SampleDecimal
{
get { return _sampleDecimal; }
set
{
// This set isn't called until after you lose focus of the control.
System.Diagnostics.Debugger.Break();
_sampleDecimal = value;
}
}
private decimal _sampleDecimal = 1.0m;
}
答案 0 :(得分:2)
更改对此的绑定:
numericUpDown1.DataBindings.Add(nameof(NumericUpDown.Value), _ed, nameof(ExampleData.SampleDecimal), false, DataSourceUpdateMode.OnPropertyChanged);
这将确保在值更改时(而不是将焦点从控件移开时)触发绑定。
如果随后您希望能够从代码中更新SampleDecimal并使其在您的numericupdown中更新,则需要在SampleData类上实现INotifyPropertyChanged接口,如下所示:
public class ExampleData : INotifyPropertyChanged
{
protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public event PropertyChangedEventHandler PropertyChanged;
public decimal SampleDecimal
{
get { return _sampleDecimal; }
set
{
_sampleDecimal = value;
OnPropertyChanged();
}
}
private decimal _sampleDecimal = 1.0m;
}