ChangeLayer

Civil Engineering Tools

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Short description

ChangeLayer — DCL layer picker with wildcard filter and “pick from drawing” option
Lists only visible layers (not off, not frozen) and supports * / ? pattern matching
Remembers the last filter via environment variable and can auto-filter based on an object’s layer

Command:

• ChangeLayer

Description:

Opens a temporary DCL dialog titled Select Layer with a filter edit box and a single-select list of layers.
Builds the layer list from the drawing’s layer table, including only layers that are not Off and not Frozen, then sorts them alphabetically.
Allows filtering the list using wildcard patterns (* and ?) and updates the list live as the filter changes.
Provides a Pick Layer from Drawing button that lets the user select an object and automatically uses that object’s layer as the filter pattern, then reopens the dialog.
On OK, returns the chosen layer name; the command then sets CLAYER to that layer and prints confirmation; on cancel, prints a cancel message.

Helper function: (if any)

• Drawing-Visible-Layers-lst — scans the LAYER table and returns a sorted list of layer names that are not Off (bit 1) and not Frozen (bit 4).
• Update-List — applies wcmatch filtering to the full layer list and repopulates the DCL list_box.
• Highlight-Layer — finds a layer name within the currently filtered list and selects/highlights it in the list box.
• Show-Dialog — loads the generated DCL file, initializes the filter field, wires action_tile handlers, runs the dialog, unloads it, and returns the dialog result code.
• LayerList-popup — orchestrates the DCL creation, dialog loop (including “pick from drawing”), persistence of last filter, and returns the selected layer name.

Functionalities:

• Visible layer enumeration — uses tblnext over LAYER and filters by flags in group code 70 to exclude Off/Frozen layers.
• Last filter persistence — reads CHLAY-LAST-FILTER from environment; defaults to * if none; saves it back on exit.
• Temporary DCL generation — writes a layerfilter.dcl-style file to a temp path using vl-filename-mktemp and open/write-line.
• Wildcard filtering — uses wcmatch against the filter pattern; treats an empty filter as *.
• Live list refresh — filter edit_box action updates filter-pat and repopulates the list box immediately.
• Single selection tracking — list_box action stores the selected index so the chosen layer can be returned on OK.
• Pick layer from drawing — dialog button exits with a special code (2), prompts entsel, extracts group code 8 (layer), sets filter to that layer, then reopens dialog.
• Cleanup — unloads the dialog, deletes the temporary DCL file, and writes the last-used filter to the environment.
• Apply current layer — c:ChangeLayer sets CLAYER to the returned layer name and prints confirmation, otherwise prints cancel/no-selection message.

Result:

If the user clicks OK after selecting a layer from the filtered list, the routine returns that layer name and the command sets it as the current layer (CLAYER).
If the user clicks Pick Layer from Drawing, the filter is replaced with the picked object’s layer and the dialog reopens to streamline selection.
If canceled or no valid list selection is made, the current layer is unchanged and a cancel/no-selection message is printed; the last filter pattern is still saved for next time.

Images, animations etc.

XAML code:

<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:src="clr-namespace:Autodesk.Windows;assembly=AdWindows">
    
<src:RibbonToolTip x:Key="ChangeLayer">
<src:RibbonToolTip.ExpandedContent>
<StackPanel>
<TextBlock Background="AntiqueWhite" TextAlignment="Left">
<Bold>Function Syntax: ChangeLayer</Bold>

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<Bold>Version: 1 Date: 09.09.2025</Bold>
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<Hyperlink>AI+https://www.theswamp.org/index.php?topic=58620.0</Hyperlink>
<LineBreak/>
<Bold>Description</Bold>
<LineBreak/>
This AutoLISP program provides an intuitive interface for managing and switching between layers in an AutoCAD drawing.
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The user is presented with a filtered, searchable, and selectable list of visible layers, including an option to pick a layer directly from an object in the drawing.
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It streamlines layer control by allowing wildcard-based filtering and persistent settings across sessions.
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<Bold>Key Functionalities:</Bold>
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  <TextBlock>
    Prompts the user with a <Run Foreground="DarkRed">dialog interface</Run> to select a layer from the list of <Run Foreground="DarkRed">visible and unfrozen layers</Run>.
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  </TextBlock>
   <TextBlock>
    Includes an <Run Foreground="DarkRed">edit box</Run> for entering a <Run Foreground="Red">wildcard-based filter</Run> (<Run Foreground="DarkRed">asterix</Run> and <Run Foreground="DarkRed">?</Run> supported).
<LineBreak/>
  </TextBlock>
  <TextBlock>
    When the filter field is <Run Foreground="DarkRed">left empty</Run>, all visible layers are displayed.
<LineBreak/>
  </TextBlock>
  <TextBlock>
    Adds a <Run Foreground="Red">Pick Layer from Drawing</Run> button that allows the user to select any entity in the drawing to <Run Foreground="DarkRed">automatically extract its layer</Run> and populate the filter.
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  </TextBlock>
  <TextBlock>
    The matching layer is <Run Foreground="DarkRed">highlighted in the list box</Run>, ready for confirmation.
<LineBreak/>
  </TextBlock>
  <TextBlock>
    The layer is <Run Foreground="Red">only changed</Run> when the user confirms with the <Run Foreground="DarkRed">OK</Run> button — <Run Foreground="DarkRed">Cancel</Run> exits with no changes.
<LineBreak/>
  </TextBlock>
  <TextBlock>
    Remembers the <Run Foreground="DarkRed">last used filter</Run> across command runs using the AutoCAD registry (<Run Foreground="Red">setenv or getenv</Run> mechanisms).
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  </TextBlock>
  <TextBlock>
    Only <Run Foreground="DarkRed">visible and unfrozen</Run> layers are considered for the list (layers that are OFF or FROZEN are skipped).
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  </TextBlock>
  <TextBlock>
    The core command can be executed using: <Run Foreground="Red">CHLAY</Run>
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  </TextBlock>
<Bold>Typical Use Case:</Bold>
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The user types <Run Foreground="Red">CHLAY</Run> in the command line.
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A dialog appears, showing all available layers (filtered using the last-used or default filter).
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The user can manually type a filter, select a layer from the list, or click <Run Foreground="Red">Pick Layer from Drawing</Run> to populate the filter and list automatically.
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Once the desired layer is highlighted, clicking <Run Foreground="DarkRed">OK</Run> sets that layer as the <Run Foreground="DarkRed">current active layer</Run>.
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<Bold>Important Commands:</Bold>
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<Run Foreground="Red">CHLAY</Run> — Launches the layer selection interface.
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<Run Foreground="Red">setenv or getenv</Run> — Used to persist the last-used filter.
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<Run Foreground="Red">entsel</Run> — Allows selecting an entity from the drawing.
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<Run Foreground="Red">assoc 8</Run> — Retrieves the layer name from the selected entity.
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<Run Foreground="Red">wcmatch</Run> — Performs wildcard-based filtering on layer names.
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<Bold>Layer Conditions:</Bold>
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Only layers that are both <Run Foreground="DarkRed">ON</Run> and <Run Foreground="DarkRed">THAWED</Run> are included in the list box.
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The logic filters layers using bitwise checks on <Run Foreground="Red">assoc 70</Run>.
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</TextBlock>
            
<Grid>
<Image Source="ChangeLayer_000.jpg" Stretch="Uniform"/>
</Grid>

<Grid>
<Image Source="ChangeLayer_001.jpg" Stretch="Uniform"/>
</Grid>


<Grid>
<Image Source="ChangeLayer_002.jpg" Stretch="Uniform"/>
</Grid>


</StackPanel>
</src:RibbonToolTip.ExpandedContent>
</src:RibbonToolTip>
</ResourceDictionary>

ChangeLayer.xaml Download XAML file