WPF designer fail to load because of System.Web Exception !!

Question

My wpf designer fails to load because it says it cannot find assembly System.web and I don't have any idea what wpf has to do with System.web

Any Idea ?

Here is one of the XAML Pages :

<UserControl x:Class="RadinFarazJamAutomationSystem.UserControls.ctrlPriceManagement"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" Height="200" Loaded="UserControl_Loaded" Width="300" FlowDirection="RightToLeft" d:DesignWidth="300">
<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition Width="1*" />
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="165*" />
    </Grid.RowDefinitions>
    <Button Content="ثبت" Grid.Row="3" Height="23" HorizontalAlignment="Left" Margin="5" Name="btnSave" VerticalAlignment="Center" Width="80" Click="btnSave_Click" Grid.Column="1" />
    <Label Content="نرخ دلار"  HorizontalAlignment="Left" Margin="5" VerticalAlignment="Center" />
    <Label Content="درصد سود مشتری" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="5" VerticalAlignment="Center" />
    <Label Content="درصد سود همکار" Grid.Row="2" Margin="5" VerticalAlignment="Center" />
    <TextBox Grid.Column="1"  HorizontalAlignment="Stretch" Margin="5" Name="txtDollarPrice" VerticalAlignment="Center"  />
    <TextBox Grid.Column="1" Grid.Row="1" HorizontalAlignment="Stretch" Margin="5" Name="txtCustomerProfit" VerticalAlignment="Top" />
    <TextBox Grid.Column="1" Grid.Row="2" Height="23" HorizontalAlignment="Stretch" Margin="5" Name="txtColleagueProfit" VerticalAlignment="Top" />
</Grid>

but this is not related to xaml because every page has the same error . Everything was fine when one day I see this error in every page and I don't know what did i do that might caused this error.

Answer 1

Just a guess but could it be that your project is targeting the client profile of the .Net Framework? If you are attempting to use types that are not included there then you would probably see an error similar to this.

http://msdn.microsoft.com/en-us/library/cc656912.aspx