How to change the values dynamically in a grid

Question

I am trying to write a function which creates a Grid which has no value in the starting and when some value is passed to it, it should show that value in that Grid dynamically. But it is not changing it dynamically.

The two user defined functions are

createGrid[rows_, column_] := (list = {}; 
  For[i = 1, i <= rows,i++, (individualColumns = {}; 
  For[j = 1, j <= column,j++, (Subscript[e,i, j]="";individualColumns = Append[individualColumns,Subscript[e,i, j]];)]; 
list = Append[list, individualColumns];)]; layoutGrid[list])

This createGrid function generates null values which is then passed to user defined function layoutGrid.

 layoutGrid[list_] := 
Panel[Grid[list, Background -> LightBlue, Spacings -> {0, 0}, ItemSize -> {0, 0},   Alignment -> {Center, Center}],ImageSize -> {780, 480}, Background -> LightBlue]

I am calling the createGrid function by passing 20 rows and 20 columns as arguments.

Dynamic[createGrid[20,20]]

It creates the Grid having 20 rows and 20 columns having no value.

In createGrid function, variable Subscript[e,i,j], i defines the row number and j defines the column number

After building the empty Grid,when I am assigning some value to Subscript[e,1,2] like

Subscript[e,1,2]=10;

It does not show in the Grid dynamically. Why?

Answer 1

You can do :

alist = ConstantArray["", {20, 20}];

Dynamic@Panel[ Grid[alist, Background -> LightBlue, Spacings -> {1, 1}, 
  ItemSize -> {0, 0}, Alignment -> {Center, Center}], 
  ImageSize -> {780, 480}, Background -> LightBlue]

alist[[1, 2]] = 10;
alist[[3]] = ConstantArray[3.14, {20}];
alist[[4, 2]] = 2.71;
alist[[4, 3]] = SpanFromLeft;
alist[[4, 4]] = 2.71;
alist[[4, 5]] = 2.71;