/// <summary>
/// Replaces text.
/// </summary>
/// <param name="offset">The starting offset of the text to be replaced.</param>
/// <param name="length">The length of the text to be replaced.</param>
/// <param name="text">The new text.</param>
/// <param name="offsetChangeMap">
/// The offsetChangeMap determines how offsets inside the old text are mapped to the new text.
/// This affects how the anchors and segments inside the replaced region behave.
/// If you pass null (the default when using one of the other overloads), the offsets are changed as
/// in OffsetChangeMappingType.Normal mode.
/// If you pass OffsetChangeMap.Empty, then everything will stay in its old place
/// (OffsetChangeMappingType.CharacterReplace mode).
/// The offsetChangeMap must be a valid 'explanation' for the document change. See
/// <see cref="OffsetChangeMap.IsValidForDocumentChange" />.
/// Passing an OffsetChangeMap to the Replace method will automatically freeze it to ensure the thread safety of the
/// resulting
/// DocumentChangeEventArgs instance.
/// </param>
public void Replace(int offset, int length, ITextSource text, OffsetChangeMap offsetChangeMap)
{
if (text == null)
{
throw new ArgumentNullException("text");
}
text = text.CreateSnapshot();
if (offsetChangeMap != null)
{
offsetChangeMap.Freeze();
}
// Ensure that all changes take place inside an update group.
// Will also take care of throwing an exception if inDocumentChanging is set.
BeginUpdate();
try
{
// protect document change against corruption by other changes inside the event handlers
inDocumentChanging = true;
try
{
// The range verification must wait until after the BeginUpdate() call because the document
// might be modified inside the UpdateStarted event.
ThrowIfRangeInvalid(offset, length);
DoReplace(offset, length, text, offsetChangeMap);
}
finally
{
inDocumentChanging = false;
}
}
finally
{
EndUpdate();
}
}
/// <summary>
/// Replaces text.
/// </summary>
/// <param name="offset">The starting offset of the text to be replaced.</param>
/// <param name="length">The length of the text to be replaced.</param>
/// <param name="text">The new text.</param>
/// <param name="offsetChangeMappingType">
/// The offsetChangeMappingType determines how offsets inside the old text are mapped to the new text.
/// This affects how the anchors and segments inside the replaced region behave.
/// </param>
public void Replace(int offset, int length, ITextSource text, OffsetChangeMappingType offsetChangeMappingType)
{
if (text == null)
{
throw new ArgumentNullException("text");
}
// Please see OffsetChangeMappingType XML comments for details on how these modes work.
switch (offsetChangeMappingType)
{
case OffsetChangeMappingType.Normal:
Replace(offset, length, text, null);
break;
case OffsetChangeMappingType.KeepAnchorBeforeInsertion:
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(
new OffsetChangeMapEntry(offset, length, text.TextLength, false, true)));
break;
case OffsetChangeMappingType.RemoveAndInsert:
if (length == 0 || text.TextLength == 0)
{
// only insertion or only removal?
// OffsetChangeMappingType doesn't matter, just use Normal.
Replace(offset, length, text, null);
}
else
{
var map = new OffsetChangeMap(2);
map.Add(new OffsetChangeMapEntry(offset, length, 0));
map.Add(new OffsetChangeMapEntry(offset, 0, text.TextLength));
map.Freeze();
Replace(offset, length, text, map);
}
break;
case OffsetChangeMappingType.CharacterReplace:
if (length == 0 || text.TextLength == 0)
{
// only insertion or only removal?
// OffsetChangeMappingType doesn't matter, just use Normal.
Replace(offset, length, text, null);
}
else if (text.TextLength > length)
{
// look at OffsetChangeMappingType.CharacterReplace XML comments on why we need to replace
// the last character
var entry = new OffsetChangeMapEntry(offset + length - 1, 1, 1 + text.TextLength - length);
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(entry));
}
else if (text.TextLength < length)
{
var entry = new OffsetChangeMapEntry(offset + text.TextLength, length - text.TextLength, 0, true, false);
Replace(offset, length, text, OffsetChangeMap.FromSingleElement(entry));
}
else
{
Replace(offset, length, text, OffsetChangeMap.Empty);
}
break;
default:
throw new ArgumentOutOfRangeException("offsetChangeMappingType", offsetChangeMappingType, "Invalid enum value");
}
}