data.cs

// create a new dialog form
frmCellFormat frmCellFormat = new frmCellFormat();

// check, if there are existing filter instructions
CellFilterInstructions cellFilterInstructions = 
    (CellFilterInstructions)JsonConvert.DeserializeObject(
        textControl1.Tables.GetItem().Cells.GetItem().Name, 
        typeof(CellFilterInstructions));

if (cellFilterInstructions == null)
{
    // create new instructions
    Color cCellBackColor = textControl1.Tables.GetItem().Cells.GetItem().CellFormat.BackColor;

    cellFilterInstructions = new CellFilterInstructions()
    {
        TrueColor = cCellBackColor,
        FalseColor = cCellBackColor
    };
}

// show the form
frmCellFormat.CellFilterInstructions = cellFilterInstructions;

if (frmCellFormat.ShowDialog() == DialogResult.OK)
{
    // save the instructions in the Name property
    textControl1.Tables.GetItem().Cells.GetItem().Name =
        JsonConvert.SerializeObject(frmCellFormat.CellFilterInstructions); 
}