Just to add to these suggestions, you probably want to optimize for production deployment.  

If you need to check the design mode in the ViewModel, you should only do so when in `DEBUG` mode, otherwise the released version will always have to perform unnecessary checks.  
When developing, if in design mode you can exit the method (or even stub out some fake data).

Put this code as the first line of your constructor (or whatever code is being called):

**C#**:



    #if DEBUG
        if (DesignerProperties.GetIsInDesignMode(new DependencyObject())) return;
    #endif

**VB**:



    #If DEBUG Then
        If DesignerProperties.GetIsInDesignMode(New DependencyObject()) Then Return
    #End If

I'm developing a networked WPF application with the MVVM pattern and it seems that it's running and connecting to servers in the designer.

I know about the IsInDesignMode property, but I'm not sure how to access it in a ViewModel.

How do I stop my ViewModel code from running in the designer?

That window is a pita but there isn't anything you can do to stop it from showing up.  

Note how the original TabPage control doesn't show up in the toolbox, it is only ever added by the custom designer for TabControl.  This is done by giving it the [ToolboxItem(false)] attribute.  And your nemesis, [Designer] attributes that select custom designers for both the TabControl and the TabPage classes.  You'd have to create your own ExtendedTabControl and make a designer for it.  This is not fun, the TabControlDesigner class is a rather elaborate designer.  It is also *internal* so you cannot derive from it.  Using a decompiler like Reflector or ILSpy is a way to peek at the code in those designers.  I cannot recommend this unless you have a large and demanding user base of picky paying programmers.

Writing code instead of trying to make this work at design time is feasible.  But do note that you have to TryCast() at runtime to convert the TabPage reference you get from the TabPages property to your derived class.

I'm trying to use the [`System.ComponentModel.DesignerCategory`](http://msdn.microsoft.com/en-us/library/system.componentmodel.designercategoryattribute.aspx) Attribtue to prevent an extended Tab Page componenet from automatically opening up in the designer.   The suggestions on other StackOverflow questions [1][Q1],[2][Q2],[3][Q3], don't seem to work.

**Here's the code on the component**




    <System.ComponentModel.DesignerCategory("Code")>
    Public Class ExtendedTabPage : Inherits Windows.Forms.TabPage

**Here's the code in my .vbproj file**





    <Compile Include="ExtendedTabPage.vb">
      <SubType>Component</SubType>
    </Compile>

I've tried initializaing the DesignerCategory Attribute with a `""` and also `"Code"`, doing rebuilds and reopening the solution, but I still get the screen below from  a double click on the component.  Do I have to remove the project SubType?  Will that affect the way the code compiles?


![Component Designer][1]


  [1]: http://i.stack.imgur.com/BjBil.png
  [Q1]: https://stackoverflow.com/questions/2138684/is-it-possible-to-tell-visual-studio-not-to-treat-a-source-file-as-a-component
  [Q2]: https://stackoverflow.com/questions/230146/is-there-an-attribute-i-can-add-to-a-class-so-it-will-be-edited-as-code-not-in
  [Q3]: https://stackoverflow.com/questions/1789603/visual-studio-make-view-code-default-using-attribute

System.ComponentModel.DesignerCategory("Code") Still Opening Designer

Ok, so I got it done by making an extra line and using a different line for the header and the details section.  It makes it a little harder to maintain, but looks better.

**Designer**:

![Better Designer][1]


**Report**:

![Better Report][2]


  [1]: http://i.stack.imgur.com/TNMQa.png
  [2]: http://i.stack.imgur.com/GtZZb.png

I'm using Crystal Reports for VS 2008 and having trouble formatting vertical table lines in the details section.

**Too Short**

When I adjust the height of the line to exactly the height of the bottom of the section:

![Too Short Designer][1]

Then the line doesn't get applied to any items after the first in the list:

![Too Short Report][2]

**Too Long**

If I drag it past the bottom of that section, then it runs amok and fills up the entire page

![Way Too Long Designer][3]

Looks like this:

![Way Too Long Report][4]

**Failed Attempts**

I've tried a bunch of different section and line heights.  I've tried right clicking the line, clicking format object, and checking 'Extend to bottom of Section when Printing'.

I've tried the SO questions [here](https://stackoverflow.com/questions/1756003/), [here](https://stackoverflow.com/questions/8551371/), [here](https://stackoverflow.com/questions/1756003/), and [here](https://stackoverflow.com/questions/12282937/how-to-resize-the-line-objects-in-crystal-reports), and none of them seem to help.



  [1]: http://i.stack.imgur.com/Lkh5k.png
  [2]: http://i.stack.imgur.com/30Kbg.png
  [3]: http://i.stack.imgur.com/RNprW.png
  [4]: http://i.stack.imgur.com/mLccp.png

Formatting Vertical Details Lines in Crystal Reports

They will be greyed out if they are not identical in all fields selected. This can depend on a related formatting field being different.

One workaround is to create an internal text parameter:

![FontFamily Internal Parameter][1]

With default value of the value you want to use for the property:

![FontFamily Internal Parameter Default Value][2]

Then set the property for each cell that should have the same formatting to this parameter individually:

![Textbox properties with parameter][3]

Repeat this for each of the relevant child properties, you will then be able to change formatting across the report by changing the parameters.

  [1]: http://i.stack.imgur.com/1DgFj.png
  [2]: http://i.stack.imgur.com/VscYN.png
  [3]: http://i.stack.imgur.com/ki2O4.png

This is very similar to the post on [Formatting multiple fields at once in RDL][1], but there are still issues with setting properties like `Size.Width` and `Font.FontSize` when the underlying data is different between selected cells.  

Here's the accepted answer: 

> Select all the controls in the designer and press <kbd>F4</kbd> for properties. Change the background color

But if falls short when there is a property that is made up of several child properties. Here's an example using font and size, each of which are comprised of several properties.

This is what it looks like when a single field is selected or when multiple fields are selected that all have the same value:

![Properties](http://i.imgur.com/9xBOZwy.png)

But if I highlight several cells that have different font sizes, or widths, I lose the ability to edit them all simultaneously.  For example if I wanted to make consistent column widths across an entire report.

Here's what the properties look like when multiple fields are selected and any of them have a different value:

![Properties - Hidden](http://i.imgur.com/89fOdti.png)

It's not ideal, but in the case of the size property, I can enter the shorthand value which includes both width and height separated by a comma and it will apply that change to all the selected cells.

But for some reason, in the Font section, I can't even do that.

### Other things I've tried:

* **Using the Formatting Toolbar** - which seems to be always greyed out for SSRS:  
 ![Toolbar](http://i.imgur.com/6K8e03o.png)

* **Using the Formatting Menu Item** - which doesn't expose the FontSize property:  
 ![MenuBar](http://i.imgur.com/qWzqjJm.png)

* **Using the Context Menu** to enter the Properties Form, which is disabled:  
 ![ContextMenu](http://i.imgur.com/ezFXJ7B.png)

[1]: https://stackoverflow.com/q/3681397/1366033