public void MergeProperties(CssPropertyAssignmentCollection sourceCollection)
{
Dictionary<WellknownCssPropertyName, CssPropertyDeclaration> fromDic = sourceCollection._myAssignments;
Dictionary<WellknownCssPropertyName, CssPropertyDeclaration> targetDic = this._myAssignments;
foreach (CssPropertyDeclaration sourceAssignment in fromDic.Values)
{
//add or replace
targetDic[sourceAssignment.WellknownPropertyName] = sourceAssignment;
}
}