/// <summary>
/// Updates properties of current object with properties of source object.
/// </summary>
/// <param name="source"></param>
public void ApplyChanges(ExpressionViewModel source)
{
CopyAllSettings(source);
}
/// <summary>
/// Copy constructor for the ExpressionViewModel object.
/// </summary>
/// <param name="source"></param>
public ExpressionViewModel(ExpressionViewModel source)
{
CopyAllSettings(source);
}
private void initializeExpression(ExpressionViewModel expression)
{
expression.ServiceUrl = ServiceUrl;
expression.UseProxy = UseProxy;
expression.ProxyUrl = ProxyUrl;
expression.Fields = Fields;
expression.PropertyChanged += Expression_PropertyChanged;
// Creates a view with the new expression as its DataContext.
// Create a copy of the old expression because updating CurrentExpression somehow changes properties
// on it via binding
ExpressionViewModel oldExpressionClone = CurrentExpression != null ? CurrentExpression.Clone() : null;
ExpressionViewModel oldExpression = CurrentExpression;
CurrentExpression = expression;
// Re-apply the settings from before updating CurrentExpression to the previous CurrentExpression
if (oldExpression != null)
oldExpression.ApplyChanges(oldExpressionClone);
expression.CancelAction = () =>
{
IsEditingExpression = false;
};
expression.SaveAction = () =>
{
var position = QueryExpressions != null ? QueryExpressions.Count : 0;
var groupID = 0;
// Performs an add where new expression is added
// to the end of the collection.
var last = QueryExpressions != null ? QueryExpressions.LastOrDefault() : null;
if (last != null)
groupID = last.GroupID + 1;
expression.GroupID = groupID;
expression.Position = position;
QueryExpressions.Insert(position, expression);
IsEditingExpression = false;
};
expression.EditAction = () =>
{
// Creates a clone of the selected item.
var selected = expression;
var clone = new ExpressionViewModel(selected);
CurrentExpression = clone;
// Default value should be allowed to be empty while editing the expression
if (CurrentExpression.ChoiceValues != null && CurrentExpression.ChoiceValues.DefaultValue != null)
CurrentExpression.ChoiceValues.DefaultValue.AllowEmptyValues = true;
// Creates a view with the clone as DataContext
clone.CancelAction = () =>
{
// Hides the view without updating the expression.
IsEditingExpression = false;
};
clone.SaveAction = () =>
{
selected.ApplyChanges(clone);
// Hides the view and updates the expression.
IsEditingExpression = false;
};
// Displays the Expression Builder.
IsEditingExpression = true;
//if (EditExpression != null)
// EditExpression(clone);
};
expression.RemoveAction = () =>
{
// Updates the collection by removing expression and updating the groupIDs
var selected = expression;
int groupID = selected.GroupID;
QueryExpressions.Remove(selected);
updateExpressionGrouping(groupID);
selected.PropertyChanged -= Expression_PropertyChanged;
};
}
/// <summary>
/// Updates serializable properties with values from another ExpressionViewModel.
/// </summary>
/// <param name="source">The source ExpressionViewModel</param>
private void CopyAllSettings(ExpressionViewModel source)
{
if (source == null) return;
IsVisible = source.IsVisible;
ServiceUrl = source.ServiceUrl;
UseProxy = source.UseProxy;
Fields = source.Fields;
OutField = source.OutField;
ExpressionLabel = source.ExpressionLabel;
if (OutField != null && Fields != null)
{
ignoreFieldUpdate = true;
Field = Fields.FirstOrDefault(f => f.Name == OutField.Name);
ignoreFieldUpdate = false;
}
Position = source.Position;
JoinedBy = source.JoinedBy;
ignoreComparisonUpdate = true;
ComparisonOperator = source.ComparisonOperator;
ignoreComparisonUpdate = false;
ChoiceValues = source.ChoiceValues != null ? new ChoiceValues(source.ChoiceValues) : null;
UseDefaultValue = source.UseDefaultValue;
IsNullValue = source.IsNullValue;
UseMultipleValues = source.UseMultipleValues;
GroupID = source.GroupID;
FieldName = source.FieldName;
FieldAlias = source.FieldAlias;
FirstInGroup = source.firstInGroup;
InMiddleOfGroup = source.InMiddleOfGroup;
LastInGroup = source.LastInGroup;
}
/// <summary>
/// Adds new expression to the collection of expressions that form the query.
/// </summary>
/// <param name="commandParameter"></param>
private void OnAdd(object commandParameter)
{
if (!CanAdd(commandParameter)) return;
ExpressionViewModel newExpression = new ExpressionViewModel();
// Create and initialize new expression.
initializeExpression(newExpression);
// Displays the Expression Builder.
IsEditingExpression = true;
//if (EditExpression != null)
// EditExpression(newExpression);
}
