internal DbExpressionBinding(DbExpression input, DbVariableReferenceExpression varRef)
{
Debug.Assert(input != null, "DbExpressionBinding input cannot be null");
Debug.Assert(varRef != null, "DbExpressionBinding variable cannot be null");
_expr = input;
_varRef = varRef;
}
public override DbExpression Visit(DbVariableReferenceExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbVariableReferenceExpression newRef;
if (this.varMappings.TryGetValue(expression, out newRef))
{
result = newRef;
}
NotifyIfChanged(expression, result);
return(result);
}
private void RebindVariable(DbVariableReferenceExpression from, DbVariableReferenceExpression to)
{
//
// The variable is only considered rebound if the name and/or type is different.
// Otherwise, the original variable reference and the new variable reference are
// equivalent, and no rebinding of references to the old variable is necessary.
//
// When considering the new/old result types, the TypeUsage instance may be equal
// or equivalent, but the EdmType must be the same instance, so that expressions
// such as a DbPropertyExpression with the DbVariableReferenceExpression as the Instance
// continue to be valid.
//
if (!from.VariableName.Equals(to.VariableName, StringComparison.Ordinal) ||
!object.ReferenceEquals(from.ResultType.EdmType, to.ResultType.EdmType) ||
!from.ResultType.EdmEquals(to.ResultType))
{
this.varMappings[from] = to;
this.OnVariableRebound(from, to);
}
}
internal DbGroupExpressionBinding(DbExpression input, DbVariableReferenceExpression inputRef, DbVariableReferenceExpression groupRef)
{
_expr = input;
_varRef = inputRef;
_groupVarRef = groupRef;
}
/// <summary> /// Typed visitor pattern method for DbVariableReferenceExpression. /// </summary> /// <param name="expression">The DbVariableReferenceExpression that is being visited.</param> /// <returns>An instance of TResultType.</returns> public abstract TResultType Visit(DbVariableReferenceExpression expression);
/// <summary>
/// Visitor pattern method for <see cref="DbVariableReferenceExpression"/>.
/// </summary>
/// <param name="expression">The DbVariableReferenceExpression that is being visited.</param>
/// <exception cref="ArgumentNullException"><paramref name="expression"/> is null</exception>
public override void Visit(DbVariableReferenceExpression expression)
{
// #433613: PreSharp warning 56506: Parameter 'expression' to this public method must be validated: A null-dereference can occur here.
EntityUtil.CheckArgumentNull(expression, "expression");
}
/// <summary> /// Visitor pattern method for DbVariableReferenceExpression. /// </summary> /// <param name="expression">The DbVariableReferenceExpression that is being visited.</param> public abstract void Visit(DbVariableReferenceExpression expression);
protected virtual void OnVariableRebound(DbVariableReferenceExpression fromVarRef, DbVariableReferenceExpression toVarRef)
{
}