internal DbGroupExpressionBinding(
DbExpression input, DbVariableReferenceExpression inputRef, DbVariableReferenceExpression groupRef)
{
_expr = input;
_varRef = inputRef;
_groupVarRef = groupRef;
}
internal DbExpressionBinding(DbExpression input, DbVariableReferenceExpression varRef)
{
DebugCheck.NotNull(input);
DebugCheck.NotNull(varRef);
_expr = input;
_varRef = varRef;
}
public override DbExpression Visit(DbVariableReferenceExpression expression)
{
Check.NotNull(expression, "expression");
DbExpression result = expression;
DbVariableReferenceExpression newRef;
if (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)
||
!ReferenceEquals(from.ResultType.EdmType, to.ResultType.EdmType)
||
!from.ResultType.EdmEquals(to.ResultType))
{
varMappings[from] = to;
OnVariableRebound(from, to);
}
}
/// <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)
{
Check.NotNull(expression, "expression");
}
/// <summary> /// When overridden in a derived class, implements the visitor pattern for /// <see /// cref="T:System.Data.Entity.Core.Common.CommandTrees.DbVariableReferenceExpression" /> /// . /// </summary> /// <returns>A result value of a specific type.</returns> /// <param name="expression"> /// The <see cref="T:System.Data.Entity.Core.Common.CommandTrees.DbVariableReferenceExpression" /> that is being visited. /// </param> public abstract TResultType Visit(DbVariableReferenceExpression expression);
/// <summary> /// When overridden in a derived class, implements the visitor pattern for /// <see cref="T:System.Data.Entity.Core.Common.CommandTrees.DbVariableReferenceExpression" /> /// . /// </summary> /// <param name="expression"> /// The <see cref="T:System.Data.Entity.Core.Common.CommandTrees.DbVariableReferenceExpression" /> that is visited. /// </param> public abstract void Visit(DbVariableReferenceExpression expression);
public override void Visit(DbVariableReferenceExpression expression)
{
}
protected virtual void OnVariableRebound(DbVariableReferenceExpression fromVarRef, DbVariableReferenceExpression toVarRef)
{
}
internal DbExpressionBinding(DbExpression input, DbVariableReferenceExpression varRef)
{
this._expr = input;
this._varRef = varRef;
}
/// <summary>
/// Visitor pattern method for <see cref="T:System.Data.Entity.Core.Common.CommandTrees.DbVariableReferenceExpression" />.
/// </summary>
/// <param name="expression"> The DbVariableReferenceExpression that is being visited. </param>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="expression" />
/// is null
/// </exception>
public override void Visit(DbVariableReferenceExpression expression)
{
Check.NotNull <DbVariableReferenceExpression>(expression, nameof(expression));
}
