Hiding Foreign Key or Children Columns Globally in Dynamic Data

A continuation of Hiding Foreign Key column Globally in Dynamic Data. Kharot here was asking in this tread Conditional display of Foreign key navigation for a way to do this same thing with the Children FieldTemplate (it took me a while to catch on ) and so here it is, it’s basically the same as previouly written but just a few changes to the attribute and the Extension method used in the previous example.

/// <summary>
/// Checks if either the Foreign Key or 
/// Children navigation fields the are hidden.
/// </summary>
/// <param name="column">The current MetaColumn.</param>
/// <returns>
/// true if either the Foreign Key or Children 
/// navigation field are set to hidden at table level
/// </returns>
public static Boolean FkIsHidden(this MetaColumn column)
{
    var fkColumn = column as MetaForeignKeyColumn;
    if (fkColumn != null)
        return fkColumn.ParentTable.
            GetAttributeOrDefault<HideFKColumnAttribute>().
            ForeignKeyFieldIsHidden;
    
    var childrenColumn = column as MetaChildrenColumn;
    if (childrenColumn != null)
        return childrenColumn.ChildTable.
            GetAttributeOrDefault<HideFKColumnAttribute>().
            ChildrenFieldIsHidden;

    return false;
}

Listing 1 – the Extension method

All I’ve done here is test for the column being a hidden in either the Parent or Children tables.

/// <summary>
/// Hides the ForeignKey or Children Navigation Column
/// </summary>
[AttributeUsage(AttributeTargets.Class)]
public class HideFKColumnAttribute : Attribute
{
    /// <summary>
    /// Gets or sets a value indicating whether [foreign key field hidden].
    /// </summary>
    /// <value>
    ///     <c>true</c> if [foreign key field hidden]; otherwise, <c>false</c>.
    /// </value>
    public Boolean ForeignKeyFieldIsHidden { get; set; }

    /// <summary>
    /// Gets or sets a value indicating whether [children field hidden].
    /// </summary>
    /// <value><c>true</c> if [children field hidden]; otherwise, <c>false</c>.</value>
    public Boolean ChildrenFieldIsHidden { get; set; }

    /// <summary>
    /// Initializes a new instance of the <see cref="HideFKColumnAttribute"/> class.
    /// </summary>
    public HideFKColumnAttribute()
    {
        ForeignKeyFieldIsHidden = false;
        ChildrenFieldIsHidden = false;
    }
}

Listing 2 – HideFKColumnAttribute

Here I’ve added a new property and done a little refactoring to make things make sense and since it’s a Foreign Key relationship I’ve left the attribute with the same name.

[HideFKColumn(
    ForeignKeyFieldIsHidden = true,
    ChildrenFieldIsHidden = true)]
public partial class Employee
{
    // code omitted for brevity
}

Listing 3 – the metadata

I’ve made no changes to the IAutoFieldGenerator so things should just work, you can now hide the Foreign Key or Children columns globally.

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