Listbox controls have an ________ method that erases all the items in the items property.

Q: Is used to describe a file that data is written to?

The term input file is used to describe a file that data is written to.

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ListBox.SelectedIndex Property
In this article
What property of the ListBox control reports the number of items stored in the ListBox if the ListBox is empty the property equals 0?
When you work with a N ___ you access data from the beginning of the file to the end of the file?
Which type of data file access allows access to any piece of data in the file without reading the data that comes before it?
Is used to describe a file that data is written to?

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ListBox.SelectedIndex Property

Reference

Definition

Examples

The following code example demonstrates how to use the SelectedIndex property with the TopIndex property to move the currently selected item to the top of the list of items in the display area of the ListBox. The example further demonstrates how to remove items using the RemoveAt method of the System.Windows.Forms.ListBox.ObjectCollection class, and how to clear all item selection using the ClearSelected method. The code first moves the currently selected item in the ListBox to the top of the list. The code then removes all items before the currently selected item and clears all selections in the ListBox. This example requires that a ListBox containing items is added to a form and that an item is currently selected in the ListBox.

private:
   void RemoveTopItems()
   {
      // Determine if the currently selected item in the ListBox 
      // is the item displayed at the top in the ListBox.
      if ( listBox1->TopIndex != listBox1->SelectedIndex )

      // Make the currently selected item the top item in the ListBox.
      listBox1->TopIndex = listBox1->SelectedIndex;

      // Remove all items before the top item in the ListBox.
      for ( int x = (listBox1->SelectedIndex - 1); x >= 0; x-- )
      {
         listBox1->Items->RemoveAt( x );
      }

      // Clear all selections in the ListBox.
      listBox1->ClearSelected();
   }

private void RemoveTopItems()
{
   // Determine if the currently selected item in the ListBox 
   // is the item displayed at the top in the ListBox.
   if (listBox1.TopIndex != listBox1.SelectedIndex)
      // Make the currently selected item the top item in the ListBox.
      listBox1.TopIndex = listBox1.SelectedIndex;

   // Remove all items before the top item in the ListBox.
   for (int x = (listBox1.SelectedIndex -1); x >= 0; x--)
   {
      listBox1.Items.RemoveAt(x);
   }

   // Clear all selections in the ListBox.
   listBox1.ClearSelected();
}

Private Sub RemoveTopItems()
   ' Determine if the currently selected item in the ListBox 
   ' is the item displayed at the top in the ListBox.
   If listBox1.TopIndex <> listBox1.SelectedIndex Then
      ' Make the currently selected item the top item in the ListBox.
      listBox1.TopIndex = listBox1.SelectedIndex
   End If
   ' Remove all items before the top item in the ListBox.
   Dim x As Integer
   For x = listBox1.SelectedIndex - 1 To 0 Step -1
      listBox1.Items.RemoveAt(x)
   Next x

   ' Clear all selections in the ListBox.
   listBox1.ClearSelected()
End Sub

Remarks

For a standard ListBox, you can use this property to determine the index of the item that is selected in the ListBox. If the SelectionMode property of the ListBox is set to either SelectionMode.MultiSimple or SelectionMode.MultiExtended (which indicates a multiple-selection ListBox) and multiple items are selected in the list, this property can return the index to any selected item.

To retrieve a collection containing the indexes of all selected items in a multiple-selection ListBox, use the SelectedIndices property. If you want to obtain the item that is currently selected in the ListBox, use the SelectedItem property. In addition, you can use the SelectedItems property to obtain all the selected items in a multiple-selection ListBox.

Applies to

This dialog is used to define a control device in the text area that can change the content of a property in an easy way. See Using Properties in the Analysis for examples of possible areas of application. For more information about how to set the options to be shown in a control, see the description for each control below. For a general description of search expressions, see Searching in TIBCO Spotfire.

You cannot display more than 1000 values in a property control. However, you should try keep down the number of available values as much as possible in order to make the control easier to use.

To reach the Property Control dialog:

Click on the Toggle Edit Mode button,
, in the text area title bar.
Comment: You can also right-click in the text area and select Edit Text Area from the pop-up menu.
In the Text Area toolbar, click on the Insert Property Control button and select which type of control to add.

Option	Description
Control type	Displays the type of property control that you have selected to add. You can choose from: Label - shows the current value of the selected property in the text area: The label can also be used with binary properties. This means that you can use it to display images as well as text. Input field - adds a text box where you can type a new value for the property: Input field (multiple lines) - adds a text box where you can type new values for a string property with multiple lines: The Input field (multiple lines) control can only be used with string properties. Drop-down list - adds a drop-down list, where the property value can be changed by selecting among predefined options: List box - adds a list box, where the property value can be changed by selecting among predefined options: List box (multiple select) - adds a list box, where the property value can be changed by selecting several predefined options: The List box (multiple select) control can only be used with multiple line string properties. Slider - adds a slider where the property values can be changed by moving the slider: The current property value is displayed in a label above the slider.
Document Properties
Select property	Click to select which property that the property control should change.
New...	Opens the New Property dialog where you can define a new property which the property control should change.
Edit...	Allows you to edit the first (default) value to use on the selected property.
Delete	Deletes the selected document property.
Script...	Opens the Script – Act on Property Change dialog where you can define a script action that should be performed whenever the document property changes its value
Data Table Properties
Data table	Select the data table of interest.
Select property	Click to select which property that the property control should change.
New...	Opens the New Property dialog where you can define a new property which the property control should change.
Edit...	Allows you to edit the first (default) value to use on the selected property.
Delete	Deletes the selected data table property.
Column Properties
Data table	Select the data table of interest.
Column	Select the column of interest.
Select property	Click to select which property that the property control should change.
New...	Opens the New Property dialog where you can define a new property which the property control should change.
Edit...	Allows you to edit the first (default) value to use on the selected property.
Delete	Deletes the selected column property.
Set property value through	Allows you to specify how the property value should be selected: Column selection - displays a list of columns to select from. Unique values in column - displays a list of values picked from a column. Expressions - displays a list of values obtained via more or less complex calculations. Fixed values - displays a list of values that you define yourself. Numerical range - displays a range of values from min to max using a specified value interval.
Settings	See the settings for each method below.

Column selection

Displays a list of columns from which you can select a column. The columns shown can be either all columns in the data table or a specified selection of columns.

Option	Description
Data table	Select the data table from which to pick columns.
Selectable columns	Lists all columns that will be available for selection in the property control. If not all columns in the data table should be available, you can type an expression to limit which columns to show. Expressions can limit the available columns to ones of a certain data type, like "DataType:Integer" or simple conditions using the column names or the beginning of the names to show, e.g., only columns beginning with A: "A". For more information about possible search expressions, see Searching in TIBCO Spotfire.
Include (None) alternative	Adds the alternative (None) to the list of available options.
Constraints...	[Available for multiple select list boxes only.] Opens the Selection Constraints dialog where you can determine whether or not there should be a min or a max number of selections possible in the list box.
Select Columns...	Opens the Select Columns dialog where you can hand-pick the columns you want to show in the control. The selected columns will receive the same boolean column property value and a search expression matching this value will automatically be added to the Selectable columns field above.

Unique values in column

Displays a list of the unique values available in a column. See Example of Property Controlled On-Demand Data for an example using this type of property control.

Option	Description
Data table	Select the data table from which to pick columns.
Column	Select the column containing the values that should be available for selection.
Selectable values	Lists all values that will be available for selection in the property control. If not all values in the column should be available, you can type an expression to limit which values to show. Expressions can limit the available values to show, e.g., only values beginning with A: "A". For more information about possible search expressions, see Searching in TIBCO Spotfire.
Include (None) alternative	Adds the alternative (None) to the list of available options.
Constraints...	[Available for multiple select list boxes only.] Opens the Selection Constraints dialog where you can determine whether or not there should be a min or a max number of selections possible in the list box.

Expressions

Available for string properties only. Displays a list of values obtained via more or less complex calculations. The expressions option provides a list of strings that can be used as expressions on an axis, or to define curves, etc. It is a special case of the fixed values option, and can only be used with string properties.

In the example above, each option has been tied to another (numerical) property which in turn can be changed using other property controls.

It is possible to copy and paste items in the list using the pop-up menu or Ctrl+C and Ctrl+V.

Option	Description
Display name	Lists a display name for each option that the end users of the control should see.
Expression	Lists the expressions that define each option.
Add...	Opens the Custom Expression dialog where you can define an expression to calculate the value. The name you select for your expression will be the Display name that the end users of the property control will see.
Edit...	Opens the Custom Expression dialog so you can edit the expression of the selected option.
Remove	Removes the selected option.
Move Up	Moves the selected option up one step.
Move Down	Moves the selected option down one step.
Include (None) alternative	Adds the alternative (None) to the list of available options.
Constraints...	[Available for multiple select list boxes only.] Opens the Selection Constraints dialog where you can determine whether or not there should be a min or a max number of selections possible in the list box.

Fixed values

Displays a list of values that you define yourself. The display name used in the control can be different from the actual value of the alternative.

It is possible to copy and paste items in the list using the pop-up menu or Ctrl+C and Ctrl+V.

Option	Description
Display name	Type a display name for each option that the end users of the control should see.
Value	Type a value for each option.
Add	Adds a new row where you can type a new option.
Remove	Removes the selected option.
Move Up	Moves the selected option up one step.
Move Down	Moves the selected option down one step.
Include (None) alternative	Adds the alternative (None) to the list of available options.
Constraints...	[Available for multiple select list boxes only.] Opens the Selection Constraints dialog where you can determine whether or not there should be a min or a max number of selections possible in the list box.

Numerical range

Displays a range of values from min to max using a specified value interval. Can be used with numerical properties only.

Option	Description
Min	Allows you to specify the min value of the numerical range.
Max	Allows you to specify the max value of the numerical range.
Value interval	Allows you to specify the interval between the tick marks in the slider. For example, with a range from 1-10 and an interval of 1, you will be able to change the slider in steps of one: If the value interval is increased to 3, the number of tick marks will be fewer and the property will increase its value by three for each step. If the max number and the interval steps do not break even, there will be a shorter interval between the last available values.
Show min and max labels	Clear the check box to remove the labels for the max and min values of the control and just keep the current property value above the control.

What property of the ListBox control reports the number of items stored in the ListBox if the ListBox is empty the property equals 0?

Items. Clear(); ListBox controls have a(n) property that reports the number of items stored in the ListBox. If the ListBox is empty, the property equals 0.

When you work with a N ___ you access data from the beginning of the file to the end of the file?

When working with a sequential access file, you access its data from the beginning of the file to the end of the file. A direct access file, on the other hand, allows you to access its data from any point within the file that you choose.

Which type of data file access allows access to any piece of data in the file without reading the data that comes before it?

Random access file in C enables us to read or write any data in our disk file without reading or writing every piece of data before it. In a random-access file, we may quickly search for data, edit it or even remove it.