WPF grid questions - setting one up programmatically

Question

I want to display a grid of images. Initially the grid will be empty and then it will gradually fill in as the images arrive from an external device, possibly in random order, i.e., I may get the image for location (1,3) and then (5,5) etc.

The dimensions will be known at runtime, but before I display the grid, so I have to set them programmatically, not in the XAML.

1. The examples I've found on the web show how to define Grid rows and columns in XAML, but how do I do it programmatically in C#, i.e., if a 5x4 Grid is specified I want to the user to see an empty 5x4 Grid initially.

2. How do I programmatically access/alter elements at individual grid locations? When the grid is empty I'll want to initially show something in each empty spot (like an "X" or a colored rectangle) and then replace it with the actual image when it arrives. In C# how do I access Grid location (x,y) to add or change what's in it?

3 Do Grids have any intrinsic scrolling ability or do I have to wrap them in a separate scrolling control, i.e.,

<ScrollViewer>
    <Grid>
    </Grid> 
</ScrollViewer>

... and if I do this can I set it for scrollbars to only appear if they are needed based on the size?

To not make the scrollbar always show up, remove the scrollviewer. It will work as intended once you remove it. — Taugenichts, Aug 14 '14 at 14:33

score 2 · Accepted Answer · edited May 23 '17 at 12:00

It's easy, see msdn

    // Create the Grid
    Grid myGrid = new Grid();
    myGrid.Width = 250;
    myGrid.Height = 100;
    myGrid.HorizontalAlignment = HorizontalAlignment.Left;
    myGrid.VerticalAlignment = VerticalAlignment.Top;
    myGrid.ShowGridLines = true;

    // Define the Columns
    ColumnDefinition colDef1 = new ColumnDefinition();
    ColumnDefinition colDef2 = new ColumnDefinition();
    ColumnDefinition colDef3 = new ColumnDefinition();
    myGrid.ColumnDefinitions.Add(colDef1);
    myGrid.ColumnDefinitions.Add(colDef2);
    myGrid.ColumnDefinitions.Add(colDef3);

    // Define the Rows
    RowDefinition rowDef1 = new RowDefinition();
    RowDefinition rowDef2 = new RowDefinition();
    RowDefinition rowDef3 = new RowDefinition();
    RowDefinition rowDef4 = new RowDefinition();
    myGrid.RowDefinitions.Add(rowDef1);
    myGrid.RowDefinitions.Add(rowDef2);
    myGrid.RowDefinitions.Add(rowDef3);
    myGrid.RowDefinitions.Add(rowDef4);

    // Add the first text cell to the Grid
    TextBlock txt1 = new TextBlock();
    txt1.Text = "2005 Products Shipped";
    txt1.FontSize = 20; 
    txt1.FontWeight = FontWeights.Bold;
    Grid.SetColumnSpan(txt1, 3);
    Grid.SetRow(txt1, 0);

    ...
    myGrid.Children.Add(txt1);
    mainWindow.Content = myGrid

Set grid position, get it (getting is more complicated)
I'd probably use ListBox in your case, with WrapPanel. You will get selection (multiple selection?) and scrolling as a bonus. Search for "wpf listbox wrappanel", to example, here is something.

Your Grid suggestions worked great (got the layout and grid lines, etc) **except** for the text. No text appears and also I don't understand how the text is inserted since you don't reference "myGrid" just the general Grid class, so how does it know you mean that particular grid? I tried replacing "Grid" with "myGrid" and got "cannot be accessed with an instance reference; qualify it with a type name instead" — user316117, Aug 14 '14 at 16:16
`Grid.SetRow()` is [attached property](http://msdn.microsoft.com/en-us/library/ms749011.aspx). And yes, you are right, my example is not complete, it miss `myGrid.Children.Add(txt1);`, but you can find a complete in the msdn link for first question answer (and some more info). — Sinatr, Aug 15 '14 at 07:12

WPF grid questions - setting one up programmatically

1 Answers1