Custom Rule Engine in WPF - MVVM

<Window x:Class="CustomRulesMVVM.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="clr-namespace:CustomRulesMVVM.ViewModels"
        Title="Custom Rule Engine" Height="377" Width="553">   
    <Grid>               
        <TabControl Height="300" HorizontalAlignment="Left" Margin="22,12,0,0" Name="tabControl1" VerticalAlignment="Top" Width="480">
            <TabItem Header="Country">
                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                    </Grid.ColumnDefinitions>
                    <Grid.DataContext>
                        <vm:CountryViewModel/>
                    </Grid.DataContext>
                    <TextBlock Height="23" HorizontalAlignment="Center" Text="Enter Country Name:" VerticalAlignment="Center" />
                    <Button Content="Check Country" Grid.Row="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center" Width="100" Command="{Binding SearchCountry}"/>                    
                    <TextBox Grid.Column="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="120" Text="{Binding MyCountry}" />
                    <TextBlock Grid.Column="1" Grid.Row="1" Height="23" HorizontalAlignment="Center" Foreground="Blue" Text="{Binding SearchCountryResult}" VerticalAlignment="Center"/>
                </Grid>
            </TabItem>
            <TabItem Header="City and Temperature">
                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                    </Grid.ColumnDefinitions>
                    <Grid.DataContext>
                        <vm:CityViewModel/>
                    </Grid.DataContext>
                    <TextBlock Height="23" HorizontalAlignment="Center" Text="Enter City Name:" VerticalAlignment="Center" />
                    <TextBox Grid.Column="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="120" Text="{Binding CityName}" />
                    <TextBlock Height="23" HorizontalAlignment="Center" Grid.Row="1" Text="Enter Temperature:" VerticalAlignment="Center" />
                    <TextBox Grid.Row="1" Grid.Column="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="120" Text="{Binding Temperature}" />
                    <Button Content="Check City and Temperature" Grid.Row="2" Grid.ColumnSpan="2" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Command="{Binding SearchCity}"/>
                    <TextBlock Grid.Column="2" Grid.Row="2" Height="46" Width="150" TextWrapping="Wrap" Foreground="Blue" HorizontalAlignment="Center" Text="{Binding SearchCityResult}" VerticalAlignment="Center"/>
                </Grid>
            </TabItem>
            <TabItem Header="City,State and Temperatures">
                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="1*"/>
                        <ColumnDefinition Width="1*"/>
                        <ColumnDefinition Width="1.4*"/>
                        <ColumnDefinition Width="0.6*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.DataContext>
                        <vm:CityStateViewModel/>
                    </Grid.DataContext>
                    <TextBlock Height="23" HorizontalAlignment="Center" Text="Enter City Name:" VerticalAlignment="Center" />
                    <TextBox Grid.Column="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="100" Text="{Binding CityName}" />
                    <TextBlock Height="23" HorizontalAlignment="Center" Grid.Column="2" Text="Enter City Temperature:" VerticalAlignment="Center"/>
                    <TextBox Grid.Column="3" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="50" Text="{Binding CityTemperature}" />
                    <TextBlock Height="23" HorizontalAlignment="Center" Grid.Row="1" Text="Enter State Name:" VerticalAlignment="Center" />
                    <TextBox Grid.Column="1" Grid.Row="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="100" Text="{Binding StateName}" />
                    <TextBlock Height="23" HorizontalAlignment="Center" Grid.Column="2" Grid.Row="1" Text="Enter State Avg Temperature:" VerticalAlignment="Center"/>
                    <TextBox Grid.Column="3" Grid.Row="1" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center"  Width="50" Text="{Binding StateTemperature}" />
                    <Button Content="Check City and State Temparatures" Grid.Row="2" Grid.ColumnSpan="2" Height="23" HorizontalAlignment="Center" VerticalAlignment="Center" Width="200" Command="{Binding SearchCityState}" />
                    <TextBlock Grid.Column="2" Grid.Row="2" Grid.ColumnSpan="2" Height="46" Width="200" Foreground="Blue" HorizontalAlignment="Center" Text="{Binding SearchCityStateResult}" VerticalAlignment="Center" TextWrapping="Wrap"/>
                </Grid>
            </TabItem>
        </TabControl>
    </Grid>
</Window>