SWMM5 Delphi GUI Darchpipe.pas Summary

 The Darchpipe.pas unit is part of the EPA SWMM (Storm Water Management Model) project and provides a dialog form used to select a standard size of arch pipe for use in the model. The form allows users to choose a pipe size from a predefined list of standard sizes or enter a custom pipe size. The dialog utilizes a TreeView component to display these options in a structured manner.

Key Features of Darchpipe.pas:

1. Form Controls:

   • Panels and Buttons:
     • Panel1, Panel2: Contain layout for form elements.
     • Button1 (OK), Button2 (Cancel): Buttons for confirming or canceling the selection.
     • TreeView1: Displays a tree structure with pipe categories and pipe sizes.
   • TreeView Structure:
     • The TreeView is divided into root nodes representing material categories, with sub-nodes for the available standard pipe sizes.
   • Pipe Selection:
     • The user selects a pipe size, and the corresponding size code and dimensions (height and width) are extracted from the TreeView selection.

2. Event Handlers:

   • FormCreate: Initializes the form and populates the TreeView with standard arch pipe sizes.
   • FormShow: Displays the currently selected pipe size in the TreeView.
   • Button1Click: Handles the OK button click event, retrieves the selected pipe size, and closes the form.
   • FormShow: Sets the correct TreeView node as selected when the form is shown.

3. Arch Pipe Selection:

   • The TreeView displays standard arch pipe sizes categorized by material type, including height x width values.
   • The user can select a standard pipe size, which is then assigned to the SizeCode, MaxHeight, and MaxWidth variables.
   • If the user selects a "Custom" option, the form allows for custom dimensions (height and width) to be set.

4. Error Handling:

   • If no pipe size is selected, the user is prompted with an error message.

Purpose:

The Darchpipe.pas unit serves as the user interface for selecting an arch pipe size or entering custom dimensions for the selected pipe. The pipe size is then used in the SWMM simulation for modeling the conveyance system. The form includes predefined pipe sizes, and the TreeView structure helps organize the options in a user-friendly manner.