MultiTrigger executes only once

My button is supposed to change colour after certain amount of mouse overs, however Multibinding doesn't work properly.

Buttons in my application has the following style:

    <Style TargetType="Button">
        <EventSetter Event="MouseEnter" Handler="OnMouseEnterButton"/>
        <Style.Triggers>
            <MultiTrigger>
                <MultiTrigger.Conditions>
                    <Condition Property="Content" Value="0"/>
                    <Condition Property="IsMouseOver" Value="False"/>
                </MultiTrigger.Conditions>

                <MultiTrigger.Setters>
                    <Setter Property="Background" Value="Green"/>
                </MultiTrigger.Setters>
            </MultiTrigger>
        </Style.Triggers>
   </Style>

My Button looks like this:

<Button Name="button1">1</Button>

With the following event handler:

private void OnMouseEnterButton(object sender, RoutedEventArgs e)
{
    ((Button)sender).Content = (int.Parse(((Button)sender).Content.ToString())) + 1;
}

However if the value of the Button.Content condition is different from initial value. For example: <Condition Property="Content" Value="10"/> Triggers stop working.

The problem is you are comparing a System.Int32 value (set in code) with a System.String value (defined in condition).

There are two ways to fix this:

1) Change style condition to:

    <Condition Property="Content">
        <Condition.Value>
            <sys:Int32>10</sys:Int32>
        </Condition.Value>
    </Condition>

where you have to add a namespace xmlns:sys="clr-namespace:System;assembly=mscorlib"

or change you code to :

((Button)sender).Content = ((int.Parse(((Button)sender).Content.ToString())) + 1).ToString();