如果false，启用数据框

Question

我在winforms-application中遇到问题。在以下代码中，我有一个数据框，以启用文本框的启用性能。启用状态取决于复选框的值。

tbAmount.DataBindings.Add("Enabled", checkBox, "Checked", 
                          false, DataSourceUpdateMode.OnPropertyChanged);

在此代码中，如果检查了复选框，则启用文本框。但是我需要它倒。如果未选中复选框，我希望启用文本框。我该如何实现？

Answer 1

这应该做到。

    Binding bind = new Binding("Enabled", checkBox, "Checked");
    bind.Format += 
        (sender, e) => 
            e.Value = !((bool)e.Value); // invert the checked value
    textBox.DataBindings.Add(bind);

Answer 2

我知道这是一个非常古老的帖子，但是多年来我一直在寻找类似的东西，并且从来没有对最终使用的东西感到非常满意。迈克·帕克（Mike Park）的答案很棒，不仅是因为它有效，而且因为它的简单程度。

我所做的就是取走迈克的答案，然后将其变成控制扩展。谢谢迈克！

根据您使用的位置和方式，您可能需要添加对System.Windows.Forms和使用System.Windows.Forms语句的参考。

    /// <summary>
    /// Creates a DataBinding that allows you to bind to the Unchecked state instead of the normal Checked state.
    /// 
    /// Sample usage: In this case, I am enabling a Button when the CheckBox is unchecked.
    ///     // Defaults to Control Enabled property.
    ///     // Always bound to the DataSource Checked property.
    ///     YourButton.DataBindings.Add(YourButton.UncheckedBinding(YourCheckBox)); 
    /// 
    ///     var binding = YourButton.UncheckedBinding(YourCheckBox);
    ///     YourButton.DataBindings.Add(binding);
    /// 
    /// Adapted - from answer by Mike Park answered Oct 18 '12 at 19:11
    /// From: Databinding Enabled if false
    /// Link: https://stackoverflow.com/questions/12961533/databinding-enabled-if-false
    /// </summary>
    /// <typeparam name="T">Constrained to be a type that inherits from ButtonBase. This includes CheckBoxes and RadionButtons.</typeparam>
    /// <param name="control">The control that will consume the DataBinding.</param>
    /// <param name="DataSource">The control to which we are binding. We will always bind to the Checked property.</param>
    /// <returns>DataBinding that is bound to the Unchecked state instead of the usual Checked state.</returns>
    public static Binding UncheckedBinding<T>(this Control control, T DataSource) where T : ButtonBase
    {
        return UncheckedBinding(control, "Enabled", DataSource);
    }
    /// <summary>
    /// Creates a DataBinding that allows you to bind to the Unchecked state instead of the normal Checked state.
    /// 
    /// Sample usage: In this case, I am enabling a Button when the CheckBox is unchecked.
    ///     // Always bound to the DataSource Checked property.
    ///     YourButton.DataBindings.Add(YourButton.UncheckedBinding("Enabled", YourCheckBox)); 
    /// 
    ///     var binding = YourButton.UncheckedBinding(YourCheckBox);
    ///     YourButton.DataBindings.Add(binding);
    ///
    /// Adapted - from answer by Mike Park answered Oct 18 '12 at 19:11
    /// From: Databinding Enabled if false
    /// Link: https://stackoverflow.com/questions/12961533/databinding-enabled-if-false
    /// </summary>
    /// <typeparam name="T">Constrained to be a type that inherits from ButtonBase. This includes CheckBoxes and RadionButtons.</typeparam>
    /// <param name="control">The control that will consume the DataBinding.</param>
    /// <param name="DataSource">The control to which we are binding. We will always bind to the Checked property.</param>
    /// <param name="PropertyName">The name of the property that is being bound.</param>
    /// <returns>DataBinding that is bound to the Unchecked state instead of the usual Checked state.</returns>
    public static Binding UncheckedBinding<T>(this Control control, string PropertyName, T DataSource) where T : ButtonBase
    {
        var binding = new Binding(PropertyName, DataSource, "Checked");
        binding.Format += (sender, e) => e.Value = !((bool)e.Value);
        return binding;
    }