StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
8157350
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
3
CommunityOwnedDate
CreationDate
2011-11-16T19:17:08.233
FavoriteCount
0
LastActivityDate
2011-11-16T20:10:54.480
LastEditDate
2011-11-16T20:10:54.480
LastEditorUserId
22539
OwnerUserId
22539
ParentId
8157140
PostTypeId
2
Score
3
ViewCount
0
LastEditorDisplayName
text
Body
ObservableCollection inherits from Collection, so it already has position-based indexing. For string-based indexing, you can look into peoples implementations of ObservableDictionary. Personally, for better performance, I've created a HashedObservableCollection deriving from ObservableCollection which contains a Dictionary of keys to indexes to speed lookup time. By overriding InsertItem, RemoveItem, and ClearItems, you keep the dictionary in sync. In my example, the keys can be of any type but we assume the key never changes - if an item is replaced, it is replaced with an object with the same key. If you want to simplify this, you can replace TKey with String. Code: <pre><code>using System; using System.Linq; using System.Collections.Generic; using System.Collections.ObjectModel; namespace foson.Utils { /// <summary> /// Represents BindableCollection indexed by a dictionary to improve lookup/replace performance. /// </summary> /// <remarks> /// Assumes that the key will not change and is unique for each element in the collection. /// Collection is not thread-safe, so calls should be made single-threaded. /// </remarks> /// <typeparam name="TValue">The type of elements contained in the BindableCollection</typeparam> /// <typeparam name="TKey">The type of the indexing key</typeparam> public class HashedBindableCollection<TValue, TKey> : ObservableCollection<TValue> { protected internal Dictionary<TKey, int> indecies = new Dictionary<TKey, int>(); protected internal Func<TValue, TKey> _keySelector; /// <summary> /// Create new HashedBindableCollection /// </summary> /// <param name="keySelector">Selector function to create key from value</param> public HashedBindableCollection(Func<TValue, TKey> keySelector) : base() { if (keySelector == null) throw new ArgumentException("keySelector"); _keySelector = keySelector; } #region Protected Methods protected override void InsertItem(int index, TValue item) { var key = _keySelector(item); if (indecies.ContainsKey(key)) throw new DuplicateKeyException(key.ToString()); if (index != this.Count) { foreach (var k in indecies.Keys.Where(k => indecies[k] >= index).ToList()) { indecies[k]++; } } base.InsertItem(index, item); indecies[key] = index; } protected override void ClearItems() { base.ClearItems(); indecies.Clear(); } protected override void RemoveItem(int index) { var item = this[index]; var key = _keySelector(item); base.RemoveItem(index); indecies.Remove(key); foreach (var k in indecies.Keys.Where(k => indecies[k] > index).ToList()) { indecies[k]--; } } #endregion public virtual bool ContainsKey(TKey key) { return indecies.ContainsKey(key); } /// <summary> /// Gets or sets the element with the specified key. If setting a new value, new value must have same key. /// </summary> /// <param name="key">Key of element to replace</param> /// <returns></returns> public virtual TValue this[TKey key] { get { return this[indecies[key]]; } set { //confirm key matches if (!_keySelector(value).Equals(key)) throw new InvalidOperationException("Key of new value does not match"); if (!indecies.ContainsKey(key)) { this.Add(value); } else { this[indecies[key]] = value; } } } /// <summary> /// Replaces element at given key with new value. New value must have same key. /// </summary> /// <param name="key">Key of element to replace</param> /// <param name="value">New value</param> /// /// <exception cref="InvalidOperationException"></exception> /// <returns>False if key not found</returns> public virtual bool Replace(TKey key, TValue value) { if (!indecies.ContainsKey(key)) return false; //confirm key matches if (!_keySelector(value).Equals(key)) throw new InvalidOperationException("Key of new value does not match"); this[indecies[key]] = value; return true; } public virtual bool Remove(TKey key) { if (!indecies.ContainsKey(key)) return false; this.RemoveAt(indecies[key]); return true; } } public class DuplicateKeyException : Exception { public string Key { get; private set; } public DuplicateKeyException(string key) : base("Attempted to insert duplicate key " + key + " in collection") { Key = key; } } } </code></pre>
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. PO.NET 4.0 Indexer with ObservableCollection
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USfoson
UserOwnerUserId
1. USfoson
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. PO.NET 4.0 Indexer with ObservableCollection
 singulars
 PostTypePostTypeId
 PTQuestion
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTAcceptedByOriginator
CommentsPostId

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.