Access a specific Shell FlyoutItem from another page in Xamarin Forms - xamarin.forms

In my AppShell.xaml.cs page I can easily access the FlyoutItems of the Shell:
accountFlyoutItem.IsEnabled = false;
accountFlyoutItem.IsVisible = false;
However, how do you access these from another page? The only way I found was to try to iterate through the "Shell.Current.FlyoutItems". Is there a simpler way I'm missing?

Shell.Current.CurrentItem is used to get the current selected flyout .
If we want to access specific FlyoutItem after you named it in xaml (<FlyoutItem x:Name="a">) , we can get it from the following two ways
Create a global public variable in AppShell and assign the value in constructor.
public ShellItem AItem;
public AppShell()
{
InitializeComponent();
RegisterRoutes();
BindingContext = this;
AItem = a;
}
//In another page
var item = (Shell.Current as AppShell).AItem;
Create a method to return the item , in this way we don't need to create the public variable .
public ShellItem GetA()
{
return a;
}
//In another page
var item = (Shell.Current as AppShell).GetA();

Related

Double Clicking on row and getting respective row values

I want to double click on any row to getting respective row values. It is an .Razor page.
First of all, I would create a component that will inherit from QuickGrid, so you can manage it easier in the future.
// CustomGrid.razor.cs
[CascadingTypeParameter( nameof(TGridItem) )]
public partial class CustomGrid<TGridItem> : QuickGrid<TGridItem>, IAsyncDisposable
{
[Inject]
private IJSRuntime JS { get; set; } // inject service in order to use JS interop
// sometimes it is mandatory to override base class parameters by your own
}
// CustomGrid.razor
#using Microsoft.AspNetCore.Components.QuickGrid // move it into the _Imports.razor
#typeparam TGridItem // QuickGrid is a generic-typed component
#inherits QuickGrid<TGridItem> // show inheritance
<div #ref="#_gridRef"> // HTML reference of current element
<QuickGrid TGridItem="TGridItem"
Items="#Items"
ItemsProvider="#ItemsProvider"
ChildContent="#ChildContent"
Class="#Class"
// more parameters... >
</QuickGrid>
</div>
Since there is no built-in functionality for adding your custom logic into QuickGrid, you will need to use some JavaScript interopability. Read about it more in docs here and here.
We need to declare some local variables in our CustomGrid.razor.cs:
private string? _rowValue; // specifies row value of currently double clicked row
private ElementReference _gridRef; // HTML element reference object that will be passed to JS function
private IJSObjectReference? _module; // JS module, a file that contains our JS functions
private DotNetObjectReference<CustomGrid<TGridItem>>? _objRef; // .NET object reference that will be passed to JS function in order to use its C# methods
And override some of the component lifecycle methods:
protected override void OnInitialized()
{
_objRef = DotNetObjectReference.Create( this ); // creates .NET object reference of current component instance
}
protected override async Task OnAfterRenderAsync( bool firstRender )
{
if( firstRender )
{
_module = await JS.InvokeAsync<IJSObjectReference>( "import", "./js/customGrid.js" ); // creates a reference of our JS module
if( _module is not null )
{
await _module.InvokeVoidAsync( "initialize", _gridRef, _objRef ); // calls our JS function and passes some arguments
}
}
}
Now, you need to create a JS module and a functions that will add desired logic for you on the first render of the CustomGrid component, like this:
// wwwroot/js/customGrid.js
export function initialize(customGrid, dotNetObj) {
if (customGrid) { // check if custom grid element exists
var rowValue;
const rows = customGrid.querySelectorAll('tbody > tr'); // get all rows except the header row
for (let i = 0; i < rows.length; i++) {
rows[i].addEventListener('dblclick', (e) => { // add event listener to current row in the loop
rowValue = e.path[1].innerText; // get innerText of current row in the loop
console.log(rowValue)
updateCurrentRowValue(rowValue, dotNetObj); // function that will return the current row value and refresh the UI
});
}
}
}
function updateCurrentRowValue(rowValue, dotNetObj) {
dotNetObj.invokeMethodAsync("UpdateCurrentRowValue", rowValue); // C# method
}
We're almost done here! If you would try to perform double click on the row, you would see an error in the console stating that CustomGrid does not contain a public method called UpdateCurrentRowValue. Let's add it like this:
[JSInvokable]
public void UpdateCurrentRowValue( string rowValue )
{
_rowValue = rowValue; // assign received rowValue from the JS function to our local _rowValue variable
StateHasChanged(); // force UI refresh
}
Now, all you need to do is to display your _rowValue:
// CustomGrid.razor
<div #ref="#_gridRef">
<QuickGrid TGridItem="TGridItem" . . . /> // collapsed for brevity
<p>Current Row Value: #_rowValue</p>
</div>
You will also need to Dispose your newly created objects of _module and _objRef using IAsyncDisposable.DisposeAsync method:
// CustomGrid.razor.cs
async ValueTask IAsyncDisposable.DisposeAsync()
{
if( _module is not null )
{
await _module.DisposeAsync();
}
_objRef?.Dispose();
}
Usage:
<CustomGrid Items="#people">
<PropertyColumn Property="#(p => p.PersonId)" Sortable="true" />
<PropertyColumn Property="#(p => p.Name)" Sortable="true" />
<PropertyColumn Property="#(p => p.BirthDate)" Format="yyyy-MM-dd" Sortable="true" />
</CustomGrid>
That should work. If you will need any help -- don't hesitate to ask!
Remarks:
This is a basic implementation of your request. It doesn't support scenarios when there are more than 1 grid on the page. It might work, but will be buggy, I guess. For that, you will need to add some more code in JS and CustomGrid code-behind. I didn't add it because it would be too much code in one answer (quite a lot of code came out here anyway).
UPD-1:
Removed custom [Parameter]s to override QuickGrid's ones and added a comment.

How to pass argument from one form to another form in ax 2012

Table has one date field. I have two form name as formA and formB ,formA has textbox and button. formB has grid with date field.
So my question is if I enter date in textbox and clicked the button of formA, entered date should be assign in grid of formB. I added table datasource of both forms. Please help me out on this.
Although behavior described by you seems to be not so standard in terms of AX, I would suggest you to use dialog form as a FormA (rather than regular form). That way you respect best practices and desired behavior is achieved easier.
Create class extending RunBase class with date field:
class FormADialog extends RunBase
{
DialogField fieldDate;
TransDate transDate;
}
Here is how we construct form controls:
protected Object Dialog()
{
Dialog dialog = super();
fieldDate = dialog.addField(extendedTypeStr(TransDate), 'Date');
return dialog;
}
The following method will retrieve values from Dialog:
public boolean getFromDialog()
{
transDate = fieldDate.value();
return super();
}
Processing logic goes here:
public void run()
{
FormBTable formBTable;
ttsbegin;
select firstOnly forUpdate formBTable;
formBTable.Date = transDate;
formBTable.write();
ttscommit;
}
The only missing thing is entry point for dialog class (represents FormA):
public static void main(Args _args)
{
FormADialog formADialog = new FormADialog();
FormDataSource formDataSource;
if (formADialog.prompt())
{
formADialog.run();
// FormB should contain menu item for dialog class for the following code
if (args && args.record() && args.record().dataSource())
{
formDataSource = args.record().dataSource();
formDataSource.research();
}
}
}
Now clicking on dialog button will update grid.
If you insist on use of approach with two regular forms. I will think of linkActive() method at the datasource of the second form. Take a look at
Tutorial Form Dynalink. A record change in the parent form notifies the child form, making it call the linkActive method which in turn calls the executeQuery method at the child table datasource.
Another approach could be as follows.
For passing parameters from one form to another a special class Args is usually used.
Initiator form prepares data for transfer within clicked() method of button control:
void clicked()
{
Args args;
FormRun formRun;
args = new Args();
args.parm(dateField.text());
args.name(formStr(FormB));
formRun = classFactory.formRunClass(args);
formRun.init();
formRun.run();
formRun.wait();
super();
}
Receiving endpoint should listen at init() method of FormB:
public void init()
{
Date passedValue;
super();
// check presence
if (element.args())
{
passedValue = str2Date(element.args().parm(), 123);
}
}
Take a look at axaptapedia.com article to see how we can pass complex set of parameters within custom made class.

how to update Visual Studio UI when using DynamicItemStart inside a vsix package

I'm implementing a DynamicItemStart button inside a Menu Controller. I'm loading the dynamic items for this button when Visual Studio starts. Everything is loaded correctly so the initialize method is called an I see all the new items in this Dynamic button. After the package is completely loaded I want to add more items to this Dynamic button, but since the package is already loaded the initialize method is not called again and I cannot see the new items in this Dynamic button. I only see the ones that were loaded when VS started.
Is there any way that I can force the update of this Dynamic button so it shows the new items?. I want to be able to update the VS UI after I added more items but outside the Initialize method.
The implementation I did is very similar to the one showed on this msdn example:
http://msdn.microsoft.com/en-us/library/bb166492.aspx
Does anyone know if an Update of the UI can be done by demand?
Any hints are greatly appreciated.
I finally got this working. The main thing is the implementation of a derived class of OleMenuCommand that implements a new constructor with a Predicate. This predicate is used to check if a new command is a match within the DynamicItemStart button.
public class DynamicItemMenuCommand : OleMenuCommand
{
private Predicate<int> matches;
public DynamicItemMenuCommand(CommandID rootId, Predicate<int> matches, EventHandler invokeHandler, EventHandler beforeQueryStatusHandler)
: base(invokeHandler, null, beforeQueryStatusHandler, rootId)
{
if (matches == null)
{
throw new ArgumentNullException("Matches predicate cannot be null.");
}
this.matches = matches;
}
public override bool DynamicItemMatch(int cmdId)
{
if (this.matches(cmdId))
{
this.MatchedCommandId = cmdId;
return true;
}
this.MatchedCommandId = 0;
return false;
}
}
The above class should be used when adding the commands on execution time. Here's the code that creates the commands
public class ListMenu
{
private int _baselistID = (int)PkgCmdIDList.cmdidMRUList;
private List<IVsDataExplorerConnection> _connectionsList;
public ListMenu(ref OleMenuCommandService mcs)
{
InitMRUMenu(ref mcs);
}
internal void InitMRUMenu(ref OleMenuCommandService mcs)
{
if (mcs != null)
{
//_baselistID has the guid value of the DynamicStartItem
CommandID dynamicItemRootId = new CommandID(GuidList.guidIDEToolbarCmdSet, _baselistID);
DynamicItemMenuCommand dynamicMenuCommand = new DynamicItemMenuCommand(dynamicItemRootId, isValidDynamicItem, OnInvokedDynamicItem, OnBeforeQueryStatusDynamicItem);
mcs.AddCommand(dynamicMenuCommand);
}
}
private bool IsValidDynamicItem(int commandId)
{
return ((commandId - _baselistID) < connectionsCount); // here is the place to put the criteria to add a new command to the dynamic button
}
private void OnInvokedDynamicItem(object sender, EventArgs args)
{
DynamicItemMenuCommand invokedCommand = (DynamicItemMenuCommand)sender;
if (null != invokedCommand)
{
.....
}
}
private void OnBeforeQueryStatusDynamicItem(object sender, EventArgs args)
{
DynamicItemMenuCommand matchedCommand = (DynamicItemMenuCommand)sender;
bool isRootItem = (matchedCommand.MatchedCommandId == 0);
matchedCommand.Enabled = true;
matchedCommand.Visible = true;
int indexForDisplay = (isRootItem ? 0 : (matchedCommand.MatchedCommandId - _baselistID));
matchedCommand.Text = "Text for the command";
matchedCommand.MatchedCommandId = 0;
}
}
I had to review a lot of documentation since it was not very clear how the commands can be added on execution time. So I hope this save some time whoever has to implement anything similar.
The missing piece for me was figuring out how to control the addition of new items.
It took me some time to figure out that the matches predicate (the IsValidDynamicItem method in the sample) controls how many items get added - as long as it returns true, the OnBeforeQueryStatusDynamicItem gets invoked and can set the details (Enabled/Visible/Checked/Text etc.) of the match to be added to the menu.

Get all descendants types of base class

I have a base class called BaseEvent and several descendants classes:
public class BaseEvent {
// the some properties
// ...
}
[MapInheritance(MapInheritanceType.ParentTable)]
public class Film : BaseEvent {
// the some properties
// ...
}
[MapInheritance(MapInheritanceType.ParentTable)]
public class Concert : BaseEvent {
// the some properties
// ...
}
I have a code which create the BaseEvent instance at runtime:
BaseEvent event = new BaseEvent();
// assign values for a properties
// ...
baseEvent.XPObjectType = Database.XPObjectTypes.SingleOrDefault(
t => t.TypeName == "MyApp.Module.BO.Events.BaseEvent");
Now, this event will be shows in BaseEvent list view.
I want to do the following: when a user click Edit button then show in list view lookup field with all descendants types. And when user saves record change ObjectType to selected value.
How can I do this?
Thanks.
PS. this is asp.net app.
I'm not sure that your approach is correct for what you are trying to achieve. First, I'll answer the question you have asked, and afterwards I'll try to explain how the XAF already provides the functionality you are trying to achieve, namely how to choose which subclass of record to create from the user interface.
In order to create a property which allows the user to choose a Type within the application, you can declare a TypeConverter:
public class EventClassInfoTypeConverter : LocalizedClassInfoTypeConverter
{
public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
{
List<Type> values = new List<Type>();
foreach (ITypeInfo info in XafTypesInfo.Instance.PersistentTypes)
{
if ((info.IsVisible && info.IsPersistent) && (info.Type != null))
{
// select BaseEvent subclasses
if (info.Type.IsSubclassOf(typeof(BaseEvent)))
values.Add(info.Type);
}
}
values.Sort(this);
values.Insert(0, null);
return new TypeConverter.StandardValuesCollection(values);
}
}
And then your base event class would look like:
public class BaseEvent: XPObject
{
public BaseEvent(Session session)
: base(session)
{ }
private Type _EventType;
[TypeConverter(typeof(EventClassInfoTypeConverter))]
public Type EventType
{
get
{
return _EventType;
}
set
{
SetPropertyValue("EventType", ref _EventType, value);
}
}
}
However, I suspect this is not the functionality you require. Modifying the value of the property will NOT change the base type of the record. That is, you will end up with a record of type BaseEvent which has a property Type equal to 'Concert' or 'Film'.
XAF already provides a mechanism for selecting the type of record to create. In your scenario, you will find that the New button is a dropdown with your different subclasses as options:
Therefore you do not need to create a 'type' property within your object. If you need a column to show the type of event in the list view, you can declare a property as follows
[PersistentAlias("XPObjectType.Name")]
public string EventType
{
get
{
return base.ClassInfo.ClassType.Name;
}
}

Flex combo box labelfunction

I have two questions regarding the Flex combo box.
The string representing the function name will be read from xml # run time.
var combo:ComboBox = new ComboBox();
combo.labelFunction = "functionName";
How can I achieve this?
So the first name, which is to be displayed in the combo box, can be only retrieved by accessing another DTO, called person and then its first name.
var combo:ComboBox = new ComboBox();
combo.labelField= "person.firstName";
My class looks like this,
public class Test
{
public var person:PersonDTO;
}
public class PersonDTO
{
public var firstName:String;
}
Is it possible to access any multi-level text using the combo box label field ?
You need to pass the function not the name.
Doing this
combo.labelFunction = "functionName";
Is passing a string.
The only work around I can think of is to make a switch statement with one case for each function you may have. Then call that with "case" from within your xml.
switch( xml.#labelfunction ){
case 'func1':
combo.labelFunction = this.func1;
break;
case 'func2':
combo.labelFunction = this.func2;
break;
}
Its hacky but should work.
ad 1) labelFunction
Calling functions when you know only the name as String is quite easy. The following snippets shows how you can execute a function that is a member of the same class. In case you need to call a function from another class replace this with the according variable name.
private function comboBox_labelFunction(item:Object):String
{
var functionName:String = myXml.#labelFunctionName;
return this[functionName](item);
}
ad 2) labelField
It's normally not possible to use "person.firstName" as labelField. However, you should be able use it within your labelFunction. Something like this should work...
private function comboBox_labelFunction(item:Object):String
{
var labelField:String = "person.firstName";
var attributeNames:Array = labelField.split(".");
for each (var attributeName:String in attributeNames)
{
if (item && item.hasOwnProperty(attributeName))
item = item[attributeName];
else
return null;
}
return item;
}

Resources