 <p>The Control is generic class, to show the decimalplaces you need to make a typecast to convert the Control to the specific type (NumericUpDown).</p> <p>Below code will work:</p> <pre><code>public CustomToolStripControlHost(Control c) : base(c) { NumericUpDown numUpDown = (NumericUpDown)c; numUpDown.DecimalPlaces = 10; } </code></pre>