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davescriven authoredc912ea85
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Svg
{
/// <summary>
/// Provides methods to ensure element ID's are valid and unique.
/// </summary>
public class SvgElementIdManager
{
private SvgDocument _document;
private Dictionary<string, SvgElement> _idValueMap;
/// <summary>
/// Retrieves the <see cref="SvgElement"/> with the specified ID.
/// </summary>
/// <param name="id">A <see cref="string"/> containing the ID of the element to find.</param>
/// <returns>An <see cref="SvgElement"/> of one exists with the specified ID; otherwise false.</returns>
public virtual SvgElement GetElementById(string id)
{
if (id.StartsWith("url("))
{
id = id.Substring(4);
id = id.TrimEnd(')');
}
if (id.StartsWith("#"))
{
id = id.Substring(1);
}
SvgElement element = null;
this._idValueMap.TryGetValue(id, out element);
return element;
}
public virtual SvgElement GetElementById(Uri uri)
{
return this.GetElementById(uri.ToString());
}
/// <summary>
/// Adds the specified <see cref="SvgElement"/> for ID management.
/// </summary>
/// <param name="element">The <see cref="SvgElement"/> to be managed.</param>
public virtual void Add(SvgElement element)
{
if (!string.IsNullOrEmpty(element.ID))
{
this.EnsureValidId(element.ID);
this._idValueMap.Add(element.ID, element);
}
OnAdded(element);
}
/// <summary>
/// Removed the specified <see cref="SvgElement"/> from ID management.
/// </summary>
/// <param name="element">The <see cref="SvgElement"/> to be removed from ID management.</param>
public virtual void Remove(SvgElement element)
{
if (!string.IsNullOrEmpty(element.ID))
{
this._idValueMap.Remove(element.ID);
}
OnRemoved(element);
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}
/// <summary>
/// Ensures that the specified ID is valid within the containing <see cref="SvgDocument"/>.
/// </summary>
/// <param name="id">A <see cref="string"/> containing the ID to validate.</param>
/// <exception cref="SvgException">
/// <para>The ID cannot start with a digit.</para>
/// <para>An element with the same ID already exists within the containing <see cref="SvgDocument"/>.</para>
/// </exception>
public void EnsureValidId(string id)
{
if (string.IsNullOrEmpty(id))
{
return;
}
if (char.IsDigit(id[0]))
{
throw new SvgException("ID cannot start with a digit: '" + id + "'.");
}
if (this._idValueMap.ContainsKey(id))
{
throw new SvgException("An element with the same ID already exists: '" + id + "'.");
}
}
/// <summary>
/// Initialises a new instance of an <see cref="SvgElementIdManager"/>.
/// </summary>
/// <param name="document">The <see cref="SvgDocument"/> containing the <see cref="SvgElement"/>s to manage.</param>
public SvgElementIdManager(SvgDocument document)
{
this._document = document;
this._idValueMap = new Dictionary<string, SvgElement>();
}
public event EventHandler<SvgElementEventArgs> ElementAdded;
public event EventHandler<SvgElementEventArgs> ElementRemoved;
protected void OnAdded(SvgElement element)
{
var handler = ElementAdded;
if(handler != null)
{
handler(this._document, new SvgElementEventArgs{ Element = element });
}
}
protected void OnRemoved(SvgElement element)
{
var handler = ElementRemoved;
if(handler != null)
{
handler(this._document, new SvgElementEventArgs{ Element = element });
}
}
}
public class SvgElementEventArgs : EventArgs
{
public SvgElement Element;
}
}