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GuidoComboBox

Overview

A GuidoComboBox is similar to a GuidoField in that it provides a text entry box into which characters can be typed. It differs because a list of values can also be supplied allowing you to quickly pick an entry from the list. Any of the common Guido switches for widgets can be used to modify the default behaviour of a combo box.

Combo boxes can be either exclusive or non exclusive. When a combo box is exclusive it disallows keyboard input and an entry into the field can only be made by picking an item from the supplied list of values. A non exclusive combo box behaves exactly the same as GuidoField in that characters can be entered from the keyboard but a list of values is also provided to assist with the input. The default behaviour is for a combo box to be exclusive.

Exclusive combo boxes have a list searching facility that assists with selecting items when the list is very large. When the combo box drop down list is visible you can type into the text area portion of the widget and the first matching list item will be scrolled into view. See the -sorted_list switch below for more information.

The standard -null true switch will affect a combo box by automatically populating the list of values with a blank item. This is important for exclusive combo boxes as it is the only way for a null or blank value to be specified.

The list of values for a combo box can be supplied in the form definition using the -value_in switch or can be set at runtime using the SclCreateGuidoForm command. See example 2 below for further information.

Synopsis

GuidoComboBox Name Body

Description

The GuidoComboBox command when processed will define a rectangular text entry region on the form with a triangle icon on the right that allows the list of supplied values to be selected. Any of the common Guido switches for widgets can be used to modify the default behaviour of a combo box.

Arguments

Name Name is a unique identifier that you assign and is used to differentiate this object from other Guido objects in the form definition. The name you assign will become the name of a variable in the Tcl interpreter that will contain the value as entered into the combo box on the form.

Body The body of the combo box may contain a number of switches to modify its default behaviour. The body begins with an opening curly brace and ends with a closing curly brace. If there is no required body the curly braces {} are required as a place holder for this argument.

Switches The following switches can be used to modify the default behaviour of the combo box

-exclusive true

-exclusive false

-value_in A0 A1 A2 A3 A4

-value_in "North Pit" "South Pit" "East Pit" "West Pit"

-value_in NP SP EP WP

-alternative_values "North Pit" "South Pit" "East Pit" "West Pit"

-no_mlt false

-no_mlt true

-alternative_mlt_keys North South East West

-assist_key false

-assist_key true

-shared_list firstStation

-sorted_list true

Common Guido switches reference

Examples

Example 1

The example form below demonstrates using GuidoComboBoxes. Note that the first combo box for sheet size is exclusive while the second is non exclusive, meaning any value can be typed for the plot scale.

# GuidoComboBox Example 1
# define the form
set formDef {
  GuidoForm form {
    -label "Using GuidoComboBoxes"
    -default_buttons
    GuidoComboBox sheetSize {
      -label "Sheet size"
      -width 10
      -format none
      -value_in A0 A1 A2 A3 A4
      -null false
    }
    GuidoComboBox scale {
      -label "Plot scale"
      -width 10
      -format integer
      -low_bound 100
      -high_bound 1000
      -value_in 250 500 1000
      -exclusive false
      -null false
    }
  }
}
# Create and run the form
SclCreateGuidoForm formHandle $formDef {}
$formHandle SclRun {}
puts "Plotting on a $sheetSize sheet at a scale of 1 is to $scale"
      

Example 2

The following example demonstrates using the runtime setValues clause available within the SclCreateGuidoForm command to set the values of the combo box lists. This method allows a more dynamic set of values to be set such as a list of file names which will be different most times you run the macro script.

# GuidoComboBox Example 2
# define the form
set formDef {
  GuidoForm form {
    -label "Using GuidoComboBoxes"
    -default_buttons
    GuidoComboBox plotFile {
      -label "Plot file"
      -width 25
      -format none
      -null false
    }
    GuidoComboBox plotter {
      -label "plotter"
      -width 25
      -format none
      -null false
    }
  }
}
# use the standard Tcl glob command to get a list of *.pf files in the current directory
set plotFileList [glob -nocomplain *.pf]
# Create the form and set the combobox lists at form creation time
SclCreateGuidoForm formHandle $formDef {
  # this will set the values used in the plotFile combobox
  set plotFile.setValues $plotFileList
  # this builds a list of plotter names to then set as the comboxbox list of values
  set plotter.setValues  [list "HP Design Jet 815mfp" "HP Design Jet 4000" "HP Design Jet 500"]
}
$formHandle SclRun {}
puts "Plotting $plotFile on the $plotter plotter"
      

Example 3

The following example demonstrates the use of the -alternative_values switch and the -no_mlt. On the pitId combo box the display list set with alternative values is more descriptive than the returned value_in list which is a pitId code. On the surveyor name combo box the -no_mlt switch has been used to prevent any language translation of the surveyor name. This combo is also exclusive false to allow a name that is not on the list to be entered.

# GuidoComboBox Example 3
# define the form
set formDef {
  GuidoForm form {
    -label "Using GuidoComboBoxes"
    -default_buttons
    GuidoComboBox pitId {
      -label "Pit name"
      -width 15
      -format none
      -value_in NP SP EP WP
      -alternative_values "North Pit" "South Pit" "East Pit" "West Pit"
      -null false
    }
    GuidoComboBox surveyor {
      -label "Surveyor"
      -width 15
      -format none
      -exclusive false
      -no_mlt true
      -value_in "T Odolite" "B Sight" "S Point" "F Station"
      -null false
    }
  }
}
# Create and run the form
SclCreateGuidoForm formHandle $formDef {}
$formHandle SclRun {}
puts "Selected pit is $pitId"
puts "Surveyor is $surveyor"
      

Example 4

The following example demonstrates the use of the -sorted_list switch and the -shared_list switch. On the form the second combo box called endLevel is set to share the list from the first combo box via the statement -shared_list startLevel. As the list of values is sorted both combo boxes have specified -sorted_list true to indicate to use the binary search method when searching the list.

The example screen capture has been slightly modified to display the drop down list with a search in progress. As the user types the first matching value is located in the list. In this instance "11" has been typed and the value "1100" has been found as the first match in the list.

# GuidoComboBox Example 4
# define the form
set formDef {
  GuidoForm form {
    -label "Using GuidoComboBoxes"
    -default_buttons
    GuidoComboBox startLevel {
      -label "Starting level"
      -width 10
      -format none
      -value_in 1000 1020 1040 1060 1080 1100 1120 1140 1160 1180 1200 1220 1240 1260 1280 1300
      -sorted_list true
      -null false
    }
    GuidoComboBox endLevel {
      -label "Ending level"
      -width 10
      -format none
      -shared_list startLevel
      -sorted_list true
      -null false
    }
  }
}
# Create and run the form
SclCreateGuidoForm formHandle $formDef {}
$formHandle SclRun {}
puts "Start level $startLevel"
puts "  End level $endLevel"      
      

See Also

Guido
GuidoForm
Common guido switches