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General
- MDriven Architecture
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MDriven Designer
- Barcode - on Android - with Xamarin and MDriven
- Catching more information in your model
- Creating CustomControl that Shows Data in a Gantt Chart
- Custom controls in ViewModel aided Views
- Delayed Fetch
- Derivation expressions
- Derived settable attributes
- Diagrams in Diagrams
- Ecomdl
- Enumerations
- Enumerations in Modlr
- Exception starting
- GuardConstraints
- Making sense of legacy data–DB Reverse
- Material Design Icons
- MDriven Designer and Modlr extensions–exporting data
- MDriven Designer–a new Rename function to save you time
- MDriven In Xamarin
- MDrivenDesignerPropertyInspectorHints
- NugetProject
- Object Identity
- PersistenceMapperWEBAPIClient
- Plugins in Modlr
- PopUp action
- PreserveLegacyFilenames
- Property inspector
- Simulate login
- Styling WPF Applications and ViewModels
- Text formatting
- The Concept application WhenAndWhereProject
- UI First–or information first
- UIOverride
- Updates to AutoForm and Debugger after latest feedback
- Using other than standard Persistence Mappers per attribute
- Using WECPOF in runtime
- WECPOF
- WECPOF Goodies
- WPF Debugger
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Modeling
- Angular Ext Component
- autocomplete
- autofocus
- BlobDownloadLink
- ClientSortable
- DataIsHtml
- DataIsImageUrl
- DataIsLink
- BlobType
- FixColSize
- FormatAttr
- HideHeading
- MaxFetch
- MaxFileSizeInBytes
- Placeholder
- Resizable
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- StringFormat
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- Autofocus
- BlobDownloadLink
- Texttype
- MaxFetch
- A few words on linq
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- ClassFromString
- Collection of strings
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- Custom types and custom operations in OCL
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- Examples on collection operators
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- Ocl hex to dec
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- Split time string to value
- State value as a string
- Understanding OCL with reference to SQL
- Unique constraints on 1 to 1 links
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- and
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- at0
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- let
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- random
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- Translate
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MDriven Turnkey
- CodeDress
- External login services in MDriven Turnkey
- Fonts
- Getting safe–limited–meta information from a Turnkey app
- How To Create a Dotnet MDriven Project
- How to Integrate Device Features in MDriven Apps Using the Navigator API
- Logging OCL in Turnkey
- Load balancing Turnkey and MDrivenServer
- MDriven on Synology
- Migrating From MDriven .NET Framework to .NET Core
- Office365 accesstoken
- Remote Turnkey access
- StartupViewTemplate
- SysDocBatch
- Use LibreOffice for PDF conversion
- Using Google Charts
- WPFMahappAndGantt
- AppWideAngularScriptIncludes
- AssetsTK
- Calling your own c - sharp .net things from Turnkey–server side
- Connecting javascript SinglePageApplications to Turnkey (SPA)
- DisplayWithVariables
- Geolocation
- Google Analytics in Turnkey app
- Google tag manager
- How to access your Turnkey site with FTP
- Javascript calling Turnkey rest
- Layout and CSS
- LiveUpdate
- MDriven turnkey Face - theme - styles - fashion
- MDriven Turnkey Series
- MDriven Turnkey theming
- Microsoft Azure
- Openid AzureAD
- OpenIdConnect access token and refresh token
- Overriding AngularJS MDriven Turnkey Views
- Pricing
- QR and barcode
- QR-Code to drive a workflow in any MDriven turnkey app
- Receive post data not known at design time
- Render data as html
- Render MVC ViewModel without turnkey
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- Samples
- Scaling out Turnkey on Azure
- Serverside Turnkey and MVC functioning
- SiteAssets
- Size in Images in Turnkey
- Streaming Client
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- Theme and style
- Theme as data
- Time zones and sanity–post for future reference
- TinyMCE editor
- Tkusercss
- Turnkey App Current state: Paused
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- Turnkey debug
- Turnkey email settings
- Turnkey extra meta tags
- Turnkey local development tips
- Turnkey MVC Controllers
- Turnkey reload automatically on script change or style change
- Turnkey sample Board Map Balls Gantt
- Turnkey sample Empty start model
- Turnkey sample InstantPoll
- Turnkey sample ProjectPlanner
- Turnkey sample ProjectPlanning
- Turnkey sample SoftConflict
- Turnkey Styling
- TurnkeySettings
- TurnkeyUserLogin
- Use c-sharp code to post to TurnkeyRest
- View/Page override
- ViewMeta
MDriven Server
- Change password MDriven Server
- Corrupt MDriven Server
- Lost password or locked out
- MDriven Server problem with evolve
- MDrivenServer, opening the built-in database
- No suitable constructor found
- SQL not trusted
- The anti-forgery token could not be decrypted
- Troubleshooting Turnkey deployment
- Duplicate IDs in the database
- CodeFoundButOutOfSync
- AppPool user
- AsyncTicket
- Automating deployment of Turnkey and MDrivenServer on IIS
- CacheInvalidation
- Communication between MDrivenServers
- Deploy Turnkey on your own Azure with OneDrive
- Emailing from an app using MDrivenServer
- Eventlog
- Fill in the email settings in the admin UI
- HardServerUrl
- Injecting the Core server command line parameters via file
- Installation of MDriven Server on Windows 7 Enterprise
- LocalhostDevCert
- LocalServers
- MDriven administrative database tables
- MDrivenServer log
- MDrivenServer Slack web hook
- MDrivenServer with Windows authentication
- MDrivenServerOverride
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- Purpose of History Server
- RecyclableMemoryStream
- Server Wide Variables
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- Setting up a History slave
- Slave and History Server
- Slave server in action
- SysAsync package
- SysSingleton.Deflate
- SysSingleton.UrlEncode
- SysSingleton GetSystemUrl
- Turnkey and MDrivenServer logs
- Use SqlServer
- VistaDB
- WSL Windows subsystem for Linux
MDriven Framework
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- Working with legacy Handles
Legacy
Explore Documentation ⬇️
- Change tracking help SQL
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- Microsoft.data
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- How Null is represented in your picklist
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- Index page
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- SOAP the protocol from the stone age
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- The combobox
- The VMClassId Explained
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- ViewModel for Business
OCLOperators isEmpty
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<message>Write the content here to display this box</message> | |||
[[Category: | === isEmpty () : Boolean === | ||
Returns true if ''self'' is empty - otherwise, returns false. | |||
{| class="wikitable" | |||
!Expression | |||
!Result | |||
|- | |||
|Sequence{2, 'a'}->isEmpty() | |||
|false | |||
|- | |||
|Sequence{null}->isEmpty() | |||
|false | |||
|- | |||
|Sequence{}->isEmpty() | |||
|true | |||
|} | |||
===== Warning! ===== | |||
'''''Never'' use''' ->isEmpty on a value type. The value will be converted to a list (with the value as its only item) and that will always evaluate as False. | |||
'''See also:''' [[Documentation:OCLOperators notEmpty|OCLOperators notEmpty]] | |||
[[Category:OCL Collection Operators]] | |||
{{Edited|July|12|2025}} | |||
Latest revision as of 05:01, 12 February 2025
This page was created by Alexandra on 2017-08-13. Last edited by Stephanie@mdriven.net on 2025-02-12.
isEmpty () : Boolean
Returns true if self is empty - otherwise, returns false.
| Expression | Result |
|---|---|
| Sequence{2, 'a'}->isEmpty() | false |
| Sequence{null}->isEmpty() | false |
| Sequence{}->isEmpty() | true |
Warning!
Never use ->isEmpty on a value type. The value will be converted to a list (with the value as its only item) and that will always evaluate as False.
See also: OCLOperators notEmpty