DgsAddPropertyListener: Difference between revisions

Revision as of 04:16, 10 July 2025

This function enables monitoring of property changes on DGS elements. When a property that has been added to the listener list changes via dgsSetProperty, it triggers the onDgsPropertyChange event.

[[{{{image}}}\|link=\|]]	Note: Property listeners only trigger when using dgsSetProperty, not when using specific setter functions

[[{{{image}}}\|link=\|]]	Note: The onDgsPropertyChange event is only triggered for properties that have been explicitly added to the listener

[[{{{image}}}\|link=\|]]	Tip: Property listeners persist until explicitly removed using dgsRemovePropertyListener or the element is destroyed

Syntax

bool dgsAddPropertyListener ( element dgsElement, string/table propertyNames )
bool dgsAddPropertyListener ( table dgsElements, string/table propertyNames )

Required Arguments

dgsElement: A DGS element or table of DGS elements to monitor.
propertyNames: A property name (string) or table of property names to listen for changes.

Returns

Returns true if the property listener was added successfully, false otherwise.

Examples

Example 1: Basic Property Monitoring

loadstring(exports.dgs:dgsImportFunction())()-- load functions

-- Create a DGS window
local window = dgsCreateWindow(200, 200, 400, 300, "Property Monitor Demo", false)

-- Add listener for position changes
dgsAddPropertyListener(window, "absPos")

-- Set up event handler
addEventHandler("onDgsPropertyChange", window, function(propertyName, newValue, oldValue)
if propertyName == "absPos" then
outputChatBox("Window moved from " .. tostring(oldValue[1]) .. "," .. tostring(oldValue[2]) ..
" to " .. tostring(newValue[1]) .. "," .. tostring(newValue[2]))
end
end)

-- Test the listener
setTimer(function()
dgsSetProperty(window, "absPos", {300, 250})
end, 2000, 1)

Example 2: Multiple Property Monitoring

loadstring(exports.dgs:dgsImportFunction())()-- load functions

-- Create a DGS button
local button = dgsCreateButton(50, 50, 200, 100, "Monitor Me", false)

-- Monitor multiple properties
dgsAddPropertyListener(button, {"text", "color", "size"})

-- Handle property changes
addEventHandler("onDgsPropertyChange", button, function(propertyName, newValue, oldValue)
outputChatBox("Property '" .. propertyName .. "' changed!")

    if propertyName == "text" then
        outputChatBox("Text changed from '" .. tostring(oldValue) .. "' to '" .. tostring(newValue) .. "'")
    elseif propertyName == "color" then
        outputChatBox("Color changed")
    elseif propertyName == "size" then
        outputChatBox("Size changed to " .. tostring(newValue[1]) .. "x" .. tostring(newValue[2]))
    end

end)

-- Test the listeners
setTimer(function()
dgsSetProperty(button, "text", "Changed Text!")
end, 1000, 1)

setTimer(function()
dgsSetProperty(button, "color", {tocolor(255, 0, 0, 255), tocolor(200, 0, 0, 255), tocolor(150, 0, 0, 255)})
end, 2000, 1)

Example 3: Monitoring Multiple Elements

loadstring(exports.dgs:dgsImportFunction())()-- load functions

-- Create multiple elements
local elements = {}
elements[1] = dgsCreateButton(100, 100, 150, 50, "Button 1", false)
elements[2] = dgsCreateButton(100, 200, 150, 50, "Button 2", false)
elements[3] = dgsCreateButton(100, 300, 150, 50, "Button 3", false)

-- Add property listeners to all elements at once
dgsAddPropertyListener(elements, "visible")

-- Handle visibility changes for all elements
for i, element in ipairs(elements) do
addEventHandler("onDgsPropertyChange", element, function(propertyName, newValue, oldValue)
if propertyName == "visible" then
local elementName = "Element " .. i
outputChatBox(elementName .. " visibility changed to " .. tostring(newValue))
end
end)
end

-- Test visibility changes
setTimer(function()
for i, element in ipairs(elements) do
dgsSetProperty(element, "visible", math.random() > 0.5)
end
end, 3000, 1)

Example 4: Real-time Position Tracking

loadstring(exports.dgs:dgsImportFunction())()-- load functions

-- Create a movable window
local trackingWindow = dgsCreateWindow(100, 100, 250, 200, "Position Tracker", false)
local positionLabel = dgsCreateLabel(10, 30, 230, 20, "Position: 100, 100", false, trackingWindow)
local sizeLabel = dgsCreateLabel(10, 60, 230, 20, "Size: 250 x 200", false, trackingWindow)

-- Monitor position and size changes
dgsAddPropertyListener(trackingWindow, {"absPos", "absSize"})

-- Update labels when properties change
addEventHandler("onDgsPropertyChange", trackingWindow, function(propertyName, newValue, oldValue)
if propertyName == "absPos" then
dgsSetProperty(positionLabel, "text", "Position: " .. newValue[1] .. ", " .. newValue[2])
elseif propertyName == "absSize" then
dgsSetProperty(sizeLabel, "text", "Size: " .. newValue[1] .. " x " .. newValue[2])
end
end)

-- Make window movable and resizable for testing
dgsSetProperty(trackingWindow, "movable", true)
dgsSetProperty(trackingWindow, "sizable", true)

Author

Mohab.

Custom Cursor Functions

Multi Language Supports

Animation

3D Element

3D Interface

3D Line

3D Image

3D Text

Browser

dgsCreateBrowser

Button

Check Box

Combo Box

Custom Renderer

Edit

Detect Area

Drag'N Drop

Grid List

Image

Memo

Label

Layout

Line

Progress Bar

Radio Button

Scale Pane

Scroll Bar

Scroll Pane

Selector

Style

Switch Button

Tab Panel

Window

Basic Shape Plugins

Circle

Quadrilateral

Rounded Rectangle

Other Plugins

Blur Box

Canvas

dgsCreateCanvas

Chart

Color Picker

Effect 3D

GIF

Gradient

Mask

Media Browser

Nine Slice

Object Preview Supports

Paste Handler

QRCode

Remote Image

Screen Source

SVG

Tooltips

@@ Line 142: / Line 142: @@
 ==See Also==
-_[[dgsRemovePropertyListener]]
+{{DGSFUNCTIONS}}
-_[[dgsGetListenedProperties]]
-_[[dgsSetProperty]]
-_[[dgsGetProperty]]
-[[Category:DGS_functions]]