c# - DynamicData - 如何在 Children.ascx.cs FieldTemplate 中显示 child 数量？

Question

MS DynamicData 的 Children.ascx.cs 文件有一个 Page_Load 方法，它返回一个超链接，上面写着“View Children”。我想将 child 的数量附加到超链接文本的末尾。以下是我的尝试。如何让超链接显示“查看子项 - # 条目”？

protected void Page_Load(object sender, EventArgs e)
{
    HyperLink1.Text = "View " + ChildrenColumn.ChildTable.DisplayName;

    //The following code gives the total entries.
    //How do I get the number of children only?
    //int entries = 0;
    //foreach (var entry in ChildrenColumn.ChildTable.GetQuery()) { entries++; }
    //string entryText = (entries == 1) ? "entry" : "entries";
    //HyperLink1.Text= HyperLink1.Text + " " + entries + " " + entryText;
}

Answer 1

其实并没有那么难。您可以将以下方法添加到您的 Children.ascx.cs 文件中:

    protected override void OnDataBinding(EventArgs e)
    {
        base.OnDataBinding(e);

        object entity;
        ICustomTypeDescriptor rowDescriptor = Row as ICustomTypeDescriptor;
        if (rowDescriptor != null)
        {
            // Get the real entity from the wrapper
            entity = rowDescriptor.GetPropertyOwner(null);
        }
        else
        {
            entity = Row;
        }

        // Get the collection and make sure it's loaded
        RelatedEnd entityCollection = Column.EntityTypeProperty.GetValue(entity, null) as RelatedEnd;
        if (entityCollection == null)
        {
            throw new InvalidOperationException(String.Format("The Children template does not support the collection type of the '{0}' column on the '{1}' table.", Column.Name, Table.Name));
        }
        if (!entityCollection.IsLoaded)
        {
            entityCollection.Load();
        }

        int count = 0;
        var enumerator = entityCollection.GetEnumerator();
        while (enumerator.MoveNext())
            count++;

        HyperLink1.Text += " (" + count + ")";
    }