能否编程创建3行2列但最后一行仅1列的Grid控件？

Absolutely—great question! I know you’re just looking to understand the implementation rather than get homework done, so let’s break this down simply.

The key here is that the underlying Grid will still have 2 columns (since the first two rows need them), but we’ll use the ColumnSpan property on the element in the last row to make it stretch across both columns. This gives the exact visual effect of the last row having a single column.

Here’s how to update your MyGrid class to implement this, including a way to populate it with example elements:

public class MyGrid : Grid 
{ 
    public void DefineRowsAndColumns() 
    {
        // Add 3 rows (using Auto to fit content size; adjust to Star/Height as needed)
        RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });
        RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });
        RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });

        // Add 2 columns (Star makes them split available space equally)
        ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Star });
        ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Star });
    }

    // Helper method to populate the grid with example elements
    public void PopulateGridWithContent()
    {
        // Row 0, Column 0
        var cell1 = new TextBlock { Text = "Row 0, Col 0", Margin = new Thickness(5) };
        Grid.SetRow(cell1, 0);
        Grid.SetColumn(cell1, 0);
        Children.Add(cell1);

        // Row 0, Column 1
        var cell2 = new TextBlock { Text = "Row 0, Col 1", Margin = new Thickness(5) };
        Grid.SetRow(cell2, 0);
        Grid.SetColumn(cell2, 1);
        Children.Add(cell2);

        // Row 1, Column 0
        var cell3 = new TextBlock { Text = "Row 1, Col 0", Margin = new Thickness(5) };
        Grid.SetRow(cell3, 1);
        Grid.SetColumn(cell3, 0);
        Children.Add(cell3);

        // Row 1, Column 1
        var cell4 = new TextBlock { Text = "Row 1, Col 1", Margin = new Thickness(5) };
        Grid.SetRow(cell4, 1);
        Grid.SetColumn(cell4, 1);
        Children.Add(cell4);

        // Row 2: spans both columns (this is the critical part!)
        var cell5 = new TextBlock { Text = "Row 2, spans both columns", Margin = new Thickness(5) };
        Grid.SetRow(cell5, 2);
        Grid.SetColumn(cell5, 0);
        Grid.SetColumnSpan(cell5, 2); // Tells the grid to stretch this element across 2 columns
        Children.Add(cell5);
    }
}

How this works: #

• Grid structure: We first define 3 rows and 2 columns. Using GridLength.Star for columns ensures they split available space equally (you can switch to GridLength.Auto or fixed pixel values if your layout needs it).
• ColumnSpan property: For the last row’s element, Grid.SetColumnSpan(cell5, 2) is the magic line. It tells the Grid to expand that element across both columns, creating the visual of a single full-width column in the last row—even though the underlying grid still has 2 columns (required for the first two rows).

Using your custom Grid: #

You’d initialize and use it like this in your code:

var myCustomGrid = new MyGrid();
myCustomGrid.DefineRowsAndColumns();
myCustomGrid.PopulateGridWithContent();
// Add the grid to your parent container (e.g., a Window or Page)

This is the standard, recommended way to achieve uneven column counts per row in WPF/UWP Grid controls—no need to modify the Grid’s core structure, just leverage the span properties!

内容的提问来源于stack exchange，提问作者Drake