How to make an element auto-expand to fill space without taking over?

I am creating a custom calendar in XAML and WPF. The calendar is made up of seven <Grid> columns that can auto expand (e.g. width="1*") with the window.

Here’s what’s happening right now:

A very wide element "takes over" the columns and makes the others smaller, which is not what I want.

I want it to look like this:

In this example, the columns auto-expand to fill available width (window size) but an element can’t make one column larger. The only way I know to achieve this is by setting the width property (but then it wouldn’t auto-expand).

Here’s sample code. It would produce output like the first image:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="1*"/>
        <ColumnDefinition Width="1*"/>
        <ColumnDefinition Width="1*"/>
        <ColumnDefinition Width="1*"/>
        <ColumnDefinition Width="1*"/>
        <ColumnDefinition Width="1*"/>
        <ColumnDefinition Width="1*"/>
    </Grid.ColumnDefinitions>
    <TextBlock Text="Hello world this is a sample very long text!" Grid.Column="1"/>
    <TextBlock Text="Hello world !" Grid.Column="2"/>
</Grid>

How can I achieve this desired output?

Edit: I was using a ScrollViewer around my grid (to vertically scroll in case there were many assignments). The property HorizontalScrollBarVisibility="Hidden" actually caused this strange behavior.

>Solution :

I am not sure its the solution for your problem, but you can try to wrap the text if overflows, like this:

<TextBlock Text="Some long text" TextWrapping="Wrap">

Let me know if this helps, if not i can look more into it!