WPF multiple bindings

Elfman

Hi All,

I'm kinda new to WPF and I've been working on a large project and getting on ok for the most part. In saying that I've recently hit a snag .

The problem is I'm using MVVM pattern and I want to make an edit form. The edit Form will have a row of labels down the left with text bound to a data context. Alined with these labels are textboxes bound to a different data source.

So for example

we read a list of field names for one places (firstname, surname, postcode) and we read the details that they align with from another say a collection of type contacts ({"Joe", "Bloggs", '1000'})

so we ened up with

firstname - |Joe |
surname - |Bloggs |
postcode - |1000 |

All of this needs to be dynamic and work regardless of if I change contact for another object type .

Can anyone point me in the right direction of the best approach to achive this.

Many thanks

RealistSpy

Have you tried binding the textbox in xaml ItemsSource="{Binding Contact}"

Loop //If needed
Contact data = new Contact (Name, Surname, PC);
TextBox1.Text = data.Name
Etc

I hope this helps a little.

SionnachRoe

This can be done in a few ways though, without seeing the rest of the system, I can't say which is best for your case.

At the core is the idea that the view binds only to a single viewmodel (datasource)

If you have a fixed number of fields
e.g.

Label1 Value1
Label2 Value2
Label3 Value3


then the viewmodel will have a fixed number of properties

string Label1Text
string Value1

string Label2Text
string Value2

string Label3Text
string Value3

and each control binds statically to a single property on the viewmodel (note: there can be some messing around here if the values can be non-string types, but one problem at a time)

There is no need for a second datasource in the XAML
There are no loops


A question is where/how these values are set. This is the variable part. We can set them in the viewmodel, passing in the two datasources (field names, and field values) or we can set them in the model (basically replicating the above values on the model and the viewmodel fields become simple passthroughs). Unfortunately, it depends on the rest of the system.

One option:
The Model contains the object to be bound.
The ViewModel is created by passing in the object to be bound and we use some mechanism (say attributes or simply reflecting through the public properties) to set the values for the labels and bind the Value properties on the viewmodel to the properties of the object.



If the number of fields varies then you will need to have a list of Label,Value pairs on the viewmodel and an items control in the Xaml which binds to the list with each item in the list binding to a Label,Value pair.


Hope this is of help,
Alan


PS:

Before putting in the work to try and implement this by hand I would have a search around for a WPF port of Silverlights DataForm control (WPF DataForm (CodePlex) or if you have a budget to buy a control (this will save a lot of development time) do a web search for WPF Dataform controls and have a look to see if any match your needs.

Elfman

Thanks for both of those replies ,
especially SionnachRoe's, very helpful thanks a million.
Going to take a look and get back to you.


cheers
Elfman