Dynamically create grid in Xamarin.Forms

The Grid gOutvariable is local to your CreateDummyGridsmethod, not passed elsewhere. So after using the method, it will be destroyed.

You need to have some kind of element in the XAML to be able to add the grid to it (or just put the grid there and add the children directly to that grid).

So add the following where you want the grid to appear:

<Grid x:Name="productGrid" />

and change yours to CreateDummyGridsthis:

public void CreateDummyGrids()
    {
        productGrid.RowDefinitions.Add(new RowDefinition());
        productGrid.RowDefinitions.Add(new RowDefinition());
        productGrid.RowDefinitions.Add(new RowDefinition());
        productGrid.ColumnDefinitions.Add(new ColumnDefinition());
        productGrid.ColumnDefinitions.Add(new ColumnDefinition());

        for (int rowIndex = 0; rowIndex < 3; rowIndex++)
        {
            for (int columnIndex = 0; columnIndex < 2; columnIndex++)
            {

                var label = new Label
                {
                   Text  ="Hello",
                    VerticalOptions = LayoutOptions.Center,
                    HorizontalOptions = LayoutOptions.Center
                };
                productGrid.Children.Add(label, columnIndex, rowIndex);
            }
        }
    }

Now keep in mind that every time this method is called, new ColumnDefinitions, RowDefinitions, and Labels are added, so if you want to keep adding stuff, you'll have to change it slightly. But I hope this is enough to get you going in the right direction