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COM Object Properties

MATLAB Functions for Object Properties

You can get the value of a property and, sometimes, change the value. You also can add custom properties.

Property names are not case-sensitive. You can abbreviate them as long as the name is unambiguous.

FunctionDescription

get

List one or more properties and their values.

set

Set the value of one or more properties.

isprop

Determine if an item is a property of a COM object.

addproperty

Add a custom property to a COM object.

deleteproperty

Remove a custom property from a COM object.

inspect

Open the Property Inspector to display and modify property values.

propedit

Display the built-in property page of the control, if any.

Work with Multiple Objects

You can use the get and set functions on more than one object at a time by creating a vector of object handles and using these commands on the vector. To get or set values for multiple objects, use the functional form of the get and set functions. Use dot notation, for example h.propname, on scalar objects only.

Enumerated Values for Properties

Enumeration makes examining and changing properties easier because each possible value for the property is assigned text to represent it. For example, one of the values for the DefaultSaveFormat property in a Microsoft® Excel® spreadsheet is xlUnicodeText. This text is easier to remember than a numeric value like 57.

Property Inspector

The Property Inspector enables you to access the properties of COM objects. To open the Property Inspector, use the inspect function from the MATLAB® command line or double-click the object in the MATLAB Workspace browser.

For example, create an Excel object. Then set the DefaultFilePath property to an existing folder, C:\ExcelWork.

h = actxserver('Excel.Application');
h.DefaultFilePath = 'C:\ExcelWork';

Display the properties of the object.

inspect(h)

Scroll down until you see the DefaultFilePath property that you just changed, C:\ExcelWork.

Using the Property Inspector, change DefaultFilePath once more, this time to another existing folder, MyWorkDirectory. To do this, select the value at the right and type the new value.

Now go back to the MATLAB Command Window and confirm that the DefaultFilePath property has changed as expected.

h.DefaultFilePath

ans =

C:\MyWorkDirectory

Note

If you modify properties at the MATLAB command line, refresh the Property Inspector window to see the change reflected there. Refresh the Property Inspector window by reinvoking the inspect function on the object.

Enumerated Values

A list button next to a property value indicates that the property accepts enumerated values. To see the values, click anywhere in the field on the right. For example, the Cursor property has four enumerated values. The current value xlDefault is displayed in the field next to the property name.

To change the value, use the list button to display the options for that property, and then click the desired value.

Custom Properties

You can add your own properties to an instance of a control using the addproperty function.

To remove custom properties from a control, use the deleteproperty function.

Properties That Take Arguments

Some COM objects have properties that accept input arguments. Internally, MATLAB handles these properties as methods, which means you use the methods or invoke functions (not the get function) to view the property.

Related Examples

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