将DataTemplate网格属性内部绑定到其列定义

<DataTemplate>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="{Binding ColumnWidth}" />
            <ColumnDefinition Width="{Binding ColumnWidth}" />
            <!-- 其他列定义 -->
        </Grid.ColumnDefinitions>
        
        <!-- 网格内容 -->
        
    </Grid>
</DataTemplate>

public class MyDataObject : INotifyPropertyChanged
{
    private GridLength _columnWidth;
    
    public GridLength ColumnWidth
    {
        get { return _columnWidth; }
        set
        {
            _columnWidth = value;
            OnPropertyChanged(nameof(ColumnWidth));
        }
    }
    
    // 其他属性和方法
    
    public event PropertyChangedEventHandler PropertyChanged;
    
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

<ItemsControl ItemsSource="{Binding MyDataObjects}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="{Binding ColumnWidth}" />
                    <ColumnDefinition Width="{Binding ColumnWidth}" />
                    <!-- 其他列定义 -->
                </Grid.ColumnDefinitions>
                
                <!-- 网格内容 -->
                
            </Grid>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>