docs(dropDownList): add supported value types

Author: marin-bratanov

components/dropdownlist/overview.md

@@ -89,7 +89,15 @@ The DropDownList provides the following features:
 * `TabIndex` - the `tabindex` attribute rendered on the dropdown.
 * `TextField` - the name of the field from the model that will be shown to the user. Defaults to `Text`.
 * `ValueField` - the name of the field from the model that will be the underlying `value`. Defaults to `Value`.
-* `Value` and `bind-Value`- get/set the value of the component, can be used for binding. If you set it to a value allowed by the model class value field, the corresponding item from the data collection will be pre-selected. Use the `bind-Value` syntax for two-way binding, for example, to a variable of our own.
+* `Value` and `bind-Value`- get/set the value of the component, can be used for binding. If you set it to a value allowed by the model class value field, the corresponding item from the data collection will be pre-selected. Use the `bind-Value` syntax for two-way binding, for example, to a variable of your own. 
+    
+    The `Value` and `ValueField` can be of types:
+
+    * `number` (such as `int`, `double` and so on)
+    * `string`
+    * `Guid`
+    * `Enum`
+
 * `Width` - the width of the dropdown in pixels.
 * Templates - they allow you to control the rendering of items in the component. See the [Templates]({%slug components/dropdownlist/templates%}) article for more details.
 * Validation - see the [Input Validation]({%slug common-features/input-validation%}) article for more details.