Programmatically add view to a GridLayout in Xamarin.Android C#

You can do this while specifying column and row span, however the process of doing this in C# is different from Java. To create the GridLayout:

//Create the Grid Layout with 2 rows and 2 columns.
GridLayout sampleGridLayout = new GridLayout(mainActivity);
sampleGridLayout.RowCount = 2;
sampleGridLayout.ColumnCount = 2;

//Assuming you're adding the GridLayout to a LinearLayout. 
//Replace the layout parameters as needed.
var gridLayoutParameters = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MatchParent, LinearLayout.LayoutParams.WrapContent);
sampleGridLayout.LayoutParameters = gridLayoutParameters;

//Create a Text View.
TextView sampleTextView1 = new TextView(mainActivity);
sampleTextView1.Text = "Sample Text 1";
//The GridLayout.LayoutParams constructor being used is this:
//GridLayout.LayoutParams(GridLayout.Spec? rowSpec, GridLayout.Spec? columnSpec)
//When invoking "Spec", the first integer is the 0 based column/row index(what row/column the view is in), the 2nd integer is the column/row span.
//So this is putting it in the first row, first column, only spanning a single cell.
var sampleTextView1Parameters = new GridLayout.LayoutParams(GridLayout.InvokeSpec(0, 1), GridLayout.InvokeSpec(0, 1));
sampleTextView1.LayoutParameters = sampleTextView1Parameters;

//Create a second Text View.
TextView sampleTextView2 = new TextView(mainActivity);
sampleTextView2.Text = "Sample Text 2";
//This is putting it in the first row, second column, only spanning a single cell.
var sampleTextView2Parameters = new GridLayout.LayoutParams(GridLayout.InvokeSpec(0, 1), GridLayout.InvokeSpec(1, 1));
sampleTextView2.LayoutParameters = sampleTextView2Parameters;

//Create a third Text View.
TextView sampleTextView3 = new TextView(mainActivity);
sampleTextView3.Text = "Sample Text 3";
//This is putting it in the second row, first column, but it spans both columns.
var sampleTextView3Parameters = new GridLayout.LayoutParams(GridLayout.InvokeSpec(1, 1), GridLayout.InvokeSpec(0, 2));
sampleTextView3.LayoutParameters = sampleTextView3Parameters;

sampleGridLayout.AddView(sampleTextView1);
sampleGridLayout.AddView(sampleTextView2);
sampleGridLayout.AddView(sampleTextView3);

This will create a GridLayout where the first row has two TextViews side by side, while the second row is a single TextView that spans both columns.