没有 XAML 的 WPF 绑定

Question

I have a WPF app with a "Grid Window". This window has no added XAML to it. I create a grid (columns and rows) then place a rectangle in each one all in C#. This allows me to make a grid where I set the 'Stroke' and show locations on the grid when I set the 'Fill'.

The entire grid is set the same, in other words, if one part of the grid is red, the whole grid is red. Currently I set the grid by iterating through all of the rectangles and setting the 'Stroke' property. That works fine but seems very slow compared to most of the other operations. I would like to bind the stroke property to a variable in the C# (unless iterating is a reasonable way to handle it).

I have looked at quite a few questions here, but most want to use XAML. My code below is based off of Binding without XAML [WPF] . No errors, the grid just never shows up.

    // put a rectangle in each square
    for (int i = 0; i < x; i++) // for each column
    {
        for (int j = 0; j < y; j++) // for each row
        {
            // create a new rectangle with name, height, width, and starting color (transparent)
            var rect = new Rectangle()
            {
                Name = $"rec{(i + 1).ToString("00")}{(j + 1).ToString("00")}", //column 5 row 2 -> rec0502
                Height = squareSize,
                Width = squareSize,
                Fill = _ColorOff
            };

            // create the binding
            var binder = new Binding
            {
                Source = _GridColor, // Brush that is updated on color change
                Path = new PropertyPath("Stroke")
            };

            // apply the binding to the rectangle
            rect.SetBinding(Rectangle.StrokeProperty, binder);
            rect.DataContext = binder;

            // place the rectangle
            Grid.SetColumn(rect, i);         // current column
            Grid.SetRow(rect, (y - j - 1));  // same row but from the bottom (puts point 0,0 at bottom left)

            // add the rectangle to the grid
            grdBattleGrid.Children.Add(rect);
        }
    }

Even if iterating is fine, I'd still like to know what I'm doing wrong.

EDIT: The color name is chosen from a ComboBox on a separate window. This updates the user settings, which in turn throws an event my "Grid Window" is subscribed to. I convert the name to a SolidColorBrush before iterating though the rectangles.

Answer 1

The most simple solution would be not to have any Binding at all. Assign _GridColor to the Rectangle's Stroke. Whenever the Color property of (the assumed SolidColorBrush) _GridColor changes, it affects all Rectangles.

public SolidColorBrush _GridColor { get; } = new SolidColorBrush(); 
...

var rect = new Rectangle
{
    Name = $"rec{(i + 1).ToString("00")}{(j + 1).ToString("00")}",
    Height = squareSize,
    Width = squareSize,
    Fill = _ColorOff,
    Stroke = _GridColor // here
};

Grid.SetColumn(rect, i);
Grid.SetRow(rect, (y - j - 1));
grdBattleGrid.Children.Add(rect);

Change the Rectangle Stroke by assigning a value to the Color property of the _GridColor Brush:

_GridColor.Color = Colors.Red;

Answer 2

You just need to set the DataContext one time for the Window , not for each Rectangle .

Is Binding your own view model class from INotifyPropertyChanged interface? Link to MS Docs