kmpdfkit_demo/Demo/Examples/Compdfkit_Tools/DigitalSignature/AddCertificationControl/AddExistedCertificationDialog.xaml

<Window x:Class="Compdfkit_Tools.DigitalSignature.AddCertificationControl.AddExistedCertificationDialog"
        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"
        xmlns:local="clr-namespace:Compdfkit_Tools.DigitalSignature.AddCertificationControl"
        xmlns:common="clr-namespace:Compdfkit_Tools.Common"
        mc:Ignorable="d"
        Title="AddExistedCertificationDialog" Height="277" Width="470">
    <Window.Resources>
        <common:TextLengthToVisibilityConverter x:Key="TextLengthToVisibilityConverter"></common:TextLengthToVisibilityConverter>
        </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <TextBlock TextWrapping="Wrap" FontSize="14" Foreground="#666666" Margin="10,0,10,0" Height="40"
                   Text="Browse digital ID files. Digital ID files are password protected. If you do not know its password, you cannot access the digital ID card.">
        </TextBlock>
        <StackPanel Grid.Row="1" Orientation="Horizontal">
            <Label Content="Files" Foreground="#43474D" FontSize="14" VerticalAlignment="Center" Margin="10,0,10,0" HorizontalAlignment="Left" Width="58"></Label>
            <Grid IsEnabled="{Binding InputEnable}">
                <TextBox Width="258" Height="28"  x:Name="FileNameText" VerticalContentAlignment="Center" TextChanged="FileNameText_TextChanged" VerticalAlignment="Center" Margin="16"/>
                <TextBlock Text="Select a file" VerticalAlignment="Center"  Margin="22" Visibility="{Binding ElementName=FileNameText, Path=Text, Converter={StaticResource TextLengthToVisibilityConverter}}" IsHitTestVisible="False"  Foreground="#BBB"></TextBlock>
            </Grid>
            <Button Content="Select File" Width="90" Height="28" FontSize="14" FontFamily="Segoe UI"></Button>
        </StackPanel>
    </Grid>
</Window>