Q:

Checking that whether a user control in present in the specific cell on mouse click in c#

How can I check that whether a usercontrol exists in the cell where the user has clicked. I have created a user control Rack.cs , just want to know that how can I check that the Rack() is present in that location or not?
If yes then do something 
    private void tableLayoutPanel1_MouseClick(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            click++;
            var pt = new Point(e.X, e.Y);

            var colWidths = this.tableLayoutPanel1.GetColumnWidths();
            var rowHeights = this.tableLayoutPanel1.GetRowHeights();

            //tableLayoutPanel1.RowStyles.Add(new RowStyle(SizeType.Absolute, 150));
            //tableLayoutPanel1.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 150F));

            int col = -1, row = -1;
            int offset = 0;
            for (int iCol = 0; iCol < this.tableLayoutPanel1.ColumnCount; ++iCol)
            {
                if (pt.X >= offset && pt.X <= (offset + colWidths[iCol]))
                {
                    col = iCol;
                    break;
                }

                offset += colWidths[iCol];
            }

            offset = 0;
            for (int iRow = 0; iRow < this.tableLayoutPanel1.RowCount; ++iRow)
            {
                if (pt.Y >= offset && pt.Y <= (offset + rowHeights[iRow]))
                {
                    row = iRow;
                    break;
                }

                offset += rowHeights[iRow];
            }

            tableLayoutPanel1.Controls.Add(racking[click], col, row);
            racking[click].setposition(row, col);
            racking[click].SetChannel(click.ToString());
            tableLayoutPanel1.ColumnStyles[col].SizeType = SizeType.AutoSize;
            Adapter.insertposition(RackID, row, col, click);

        }
        else if (e.Button == MouseButtons.Right)
        {
            int[] colWidths = tableLayoutPanel1.GetColumnWidths();
            int[] rowHeights = tableLayoutPanel1.GetRowHeights();
            int top = tableLayoutPanel1.Parent.PointToScreen(tableLayoutPanel1.Location).Y;
            for (int y = 0; y < rowHeights.Length; ++y)
            {
                int left = tableLayoutPanel1.Parent.PointToScreen(tableLayoutPanel1.Location).X;
                for (int x = 0; x < colWidths.Length; ++x)
                {
                    if (new Rectangle(left, top, colWidths[x], rowHeights[y])
                                      .Contains(MousePosition))
                    {
                        Control c = tableLayoutPanel1.GetControlFromPosition(x, y);
                        if (c != null)
                        {
                            MessageBox.Show("Yes");
                        }
                    }
                    left += colWidths[x];
                }
                top += rowHeights[y];
            }
        }

        }

Now I want to check my Rack control instead of the Rectangle control that where it is present or not? And my Rack control is a mixture of text boxes and button

A:

After seeing some code it is still not entirely clear what you are doing (for example, what is racking?), but this should help anyway...
TableLayoutPanel has a method called GetControlFromPosition which will get the control within a given cell (column and row), so firstly you can get that control like so:
var myCellControl = tableLayoutPanel1.GetControlFromPosition(col, row);

What you do next will depend on how you are adding your controls. If you are directly adding a Rack control to each cell, then you can just test it like so:
if(myCellControl is Rack)
{
    //is Rack control, so do someting
}

otherwise, if the Rack control is nested within a container control (e.g. a Panel), then you should loop the children controls and test for a Rack control:
bool hasRack = false;
foreach(Control child in myCellControl.Controls)
{
    if(child is Rack)
    {
        //Rack control found
        hasRack = true;
        break;
    }
}

Hope that helps

