ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Catalog Namespace / OpenItemDialog Class / MultiSelect Property
Example Version

MultiSelect Property
Gets and sets if the Browse dialog box will support selecting many items.
Syntax
public bool MultiSelect {get; set;}
Remarks
By default, you can only select a single item in the Browse dialog box.
Example
Show_OpenItemDialog
OpenItemDialog addToProjectDialog = new OpenItemDialog();
addToProjectDialog.Title = "Add To Project";
addToProjectDialog.InitialLocation = @"C:\Data\NewYork\Counties\Maps";
addToProjectDialog.MultiSelect = true;
addToProjectDialog.Filter = ItemFilters.Composite_Maps_Import;

bool? ok = addToMapDialog.ShowDialog();

if (ok == true)
{
  IEnumerable<Item> selectedItems = addToMapDialog.Items;
  foreach (Item selectedItem in selectedItems)
    MapFactory.Instance.CreateMapFromItem(selectedItem);
}
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also