如何使用WPF隐藏RichTextBox或TextBox中的部分文本？

Question

i would like to ask for aa way in wpf of hiding and unhiding some specific lines in a richtextbox or textbox using C# at Runtime and at the same time leave the rest of the lines visible. I would also like not to be a visible space between the visible and unvisible lines. i have an idea of selecting the lines and then change font size to 0.01, but it isnt so much elegand. thanks in advance.

Answer 1

By default, you can only hide and show certain text in a WPF TextBox or RichTextBox by changing the value of the Text or RichText properties respectively. For example if you have the text "Mary had a little lamb who's fleece was white as snow" and wanted to hide the text "who's fleece was white as snow" conditonaly you would have to parse the text and remove or add "who's fleece was white as snow" in the correct location in the Text or RichText using code.

It sounds like you are just trying to modify the layout depending on certain conditions though. In that case, it is better to split the lines up into separate TextBoxes and set the visibility of those textboxes to Collapsed when certain conditions exist and set them to Visible otherwise.

If you are using TextBox you will want an outer Border which will help you match the style of TextBox, then you can set the BorderBrush and Background of the textboxes you are hiding to Transparent so it just looks like a single TextBox.

<Border
    BorderThickness="1"
    BorderBrush="Black"
    Background="White">
    <StackPanel>
        <TextBox
            Text="Mary had a little lamb "
            BorderBrush="Transparent"
            Background="Transparent" />

        <!-- Set the Visisibility Property of this TextBox in code to show or hide it -->
        <TextBox
            Name="ConditionalTextBoxLine"
            Visibility="Visible"
            Text="Who's fleece was white as snow"
            BorderBrush="Transparent"
            Background="Transparent" />
    </StackPanel>
</Border>