BindingContext.cs source code in C# .NET

                        Code:
                         / Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / Orcas / QFE / ndp / fx / src / DataEntity / System / Data / Objects / ELinq / BindingContext.cs / 2 / BindingContext.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....]
//--------------------------------------------------------------------- 
 
using CqtExpression = System.Data.Common.CommandTrees.DbExpression;
using LinqExpression = System.Linq.Expressions.Expression; 
using System.Linq.Expressions;
using System.Collections.ObjectModel;
using System.Linq;
using System.Collections.Generic; 
using System.Data.Common.CommandTrees;
using System.Data.Metadata.Edm; 
using System.Reflection; 
using System.Data.Common.EntitySql;
using System.Diagnostics; 
using System.Data.Common;
using System.Globalization;
namespace System.Data.Objects.ELinq
{ 
    /// 
    /// Class containing binding information for an expression converter (associating CQT bindings 
    /// with LINQ lambda parameter) 
    /// 
    ///  
    /// Usage pattern:
    /// 
    /// BindingContext context = ...;
    /// 
    /// // translate a "Where" lamba expression input.Where(i => i.X > 2);
    /// LambdaExpression whereLambda = ...; 
    /// CqtExpression inputCqt = Translate(whereLambda.Arguments[1]); 
    /// CqtExpression inputBinding = CreateExpressionBinding(inputCqt).Var;
    /// 
    /// // push the scope defined by the parameter
    /// context.PushBindingScope(new KeyValuePair{ParameterExpression, CqtExpression}(whereLambda.Parameters[0], inputBinding));
    ///
    /// // translate the expression in this context 
    /// CqtExpression result = Translate(whereLambda.Expression);
    /// 
    /// // pop the scope 
    /// context.PopBindingScope();
    ///  
    /// 
    internal sealed class BindingContext
    {
        private readonly Binding _rootContextBinding; 
        private readonly List _scopes;
        internal readonly ObjectContext ObjectContext; 
 
        /// 
        /// Initialize a new binding context 
        /// 
        internal BindingContext(ParameterExpression rootContextParameter, ObjectContext objectContext, CompiledQueryParameter [] compiledQueryParameters )
            : this()
        { 
            Debug.Assert(null != rootContextParameter && null != objectContext, "missing required args to BindingContext");
            _rootContextBinding = new Binding(rootContextParameter, null); 
            this.ObjectContext = objectContext; 
            PushBindingScope(_rootContextBinding);
            foreach (var parameter in compiledQueryParameters) 
            {
                Binding binding = new Binding(parameter.Expression, parameter.ParameterReference);
                PushBindingScope(binding);
            } 
        }
        ///  
        /// Initialize a new binding context 
        /// 
        internal BindingContext() 
        {
            _scopes = new List();
        }
 
        /// 
        /// Set up a new binding scope where parameter expressions map to their paired CQT expressions. 
        ///  
        /// Parameter/Expression bindings
        internal void PushBindingScope(params Binding[] bindings) 
        {
            _scopes.Add(bindings);
        }
 
        /// 
        /// Removes a scope when leaving a particular sub-expression. 
        ///  
        /// Scope.
        internal void PopBindingScope() 
        {
            _scopes.RemoveAt(_scopes.Count - 1);
        }
 
        internal bool TryGetBoundExpression(Expression linqExpression, out CqtExpression cqtExpression)
        { 
            Binding binding; 
            if (TryGetBinding(linqExpression, out binding))
            { 
                if (binding != _rootContextBinding)
                {
                    cqtExpression = binding.CqtExpression;
                    return true; 
                }
            } 
 
            cqtExpression = null;
            return false; 
        }

        internal bool IsRootContextParameter(ParameterExpression parameter)
        { 
            Binding binding;
            if (TryGetBinding(parameter, out binding)) 
            { 
                return _rootContextBinding == binding;
            } 

            return false;
        }
 
        // Try to find a CQT expression that is the translation of a LINQ parameter.
        private bool TryGetBinding(Expression parameter, out Binding binding) 
        { 
            binding = null;
 
            // if there are no binding scopes, their can be no binding
            if (_scopes.Count == 0) { return false; }

            for (int i = _scopes.Count - 1; i >= 0; i--) 
            {
                Binding[] scope = _scopes[i]; 
 
                foreach (Binding scopeBinding in scope)
                { 
                    if (parameter == scopeBinding.LinqExpression)
                    {
                        binding = scopeBinding;
                        return true; 
                    }
                } 
            } 

            // no match found 
            return false;
        }
    }
 
    /// 
    /// Class describing a LINQ parameter and its bound expression. For instance, in 
    /// 
    /// products.Select(p => p.ID)
    /// 
    /// the 'products' query is the bound expression, and 'p' is the parameter.
    /// 
    internal sealed class Binding
    { 
        internal Binding(Expression linqExpression, CqtExpression cqtExpression)
        { 
            LinqExpression = linqExpression; 
            CqtExpression = cqtExpression;
        } 

        internal readonly Expression LinqExpression;
        internal readonly CqtExpression CqtExpression;
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....]
//--------------------------------------------------------------------- 
 
using CqtExpression = System.Data.Common.CommandTrees.DbExpression;
using LinqExpression = System.Linq.Expressions.Expression; 
using System.Linq.Expressions;
using System.Collections.ObjectModel;
using System.Linq;
using System.Collections.Generic; 
using System.Data.Common.CommandTrees;
using System.Data.Metadata.Edm; 
using System.Reflection; 
using System.Data.Common.EntitySql;
using System.Diagnostics; 
using System.Data.Common;
using System.Globalization;
namespace System.Data.Objects.ELinq
{ 
    /// 
    /// Class containing binding information for an expression converter (associating CQT bindings 
    /// with LINQ lambda parameter) 
    /// 
    ///  
    /// Usage pattern:
    /// 
    /// BindingContext context = ...;
    /// 
    /// // translate a "Where" lamba expression input.Where(i => i.X > 2);
    /// LambdaExpression whereLambda = ...; 
    /// CqtExpression inputCqt = Translate(whereLambda.Arguments[1]); 
    /// CqtExpression inputBinding = CreateExpressionBinding(inputCqt).Var;
    /// 
    /// // push the scope defined by the parameter
    /// context.PushBindingScope(new KeyValuePair{ParameterExpression, CqtExpression}(whereLambda.Parameters[0], inputBinding));
    ///
    /// // translate the expression in this context 
    /// CqtExpression result = Translate(whereLambda.Expression);
    /// 
    /// // pop the scope 
    /// context.PopBindingScope();
    ///  
    /// 
    internal sealed class BindingContext
    {
        private readonly Binding _rootContextBinding; 
        private readonly List _scopes;
        internal readonly ObjectContext ObjectContext; 
 
        /// 
        /// Initialize a new binding context 
        /// 
        internal BindingContext(ParameterExpression rootContextParameter, ObjectContext objectContext, CompiledQueryParameter [] compiledQueryParameters )
            : this()
        { 
            Debug.Assert(null != rootContextParameter && null != objectContext, "missing required args to BindingContext");
            _rootContextBinding = new Binding(rootContextParameter, null); 
            this.ObjectContext = objectContext; 
            PushBindingScope(_rootContextBinding);
            foreach (var parameter in compiledQueryParameters) 
            {
                Binding binding = new Binding(parameter.Expression, parameter.ParameterReference);
                PushBindingScope(binding);
            } 
        }
        ///  
        /// Initialize a new binding context 
        /// 
        internal BindingContext() 
        {
            _scopes = new List();
        }
 
        /// 
        /// Set up a new binding scope where parameter expressions map to their paired CQT expressions. 
        ///  
        /// Parameter/Expression bindings
        internal void PushBindingScope(params Binding[] bindings) 
        {
            _scopes.Add(bindings);
        }
 
        /// 
        /// Removes a scope when leaving a particular sub-expression. 
        ///  
        /// Scope.
        internal void PopBindingScope() 
        {
            _scopes.RemoveAt(_scopes.Count - 1);
        }
 
        internal bool TryGetBoundExpression(Expression linqExpression, out CqtExpression cqtExpression)
        { 
            Binding binding; 
            if (TryGetBinding(linqExpression, out binding))
            { 
                if (binding != _rootContextBinding)
                {
                    cqtExpression = binding.CqtExpression;
                    return true; 
                }
            } 
 
            cqtExpression = null;
            return false; 
        }

        internal bool IsRootContextParameter(ParameterExpression parameter)
        { 
            Binding binding;
            if (TryGetBinding(parameter, out binding)) 
            { 
                return _rootContextBinding == binding;
            } 

            return false;
        }
 
        // Try to find a CQT expression that is the translation of a LINQ parameter.
        private bool TryGetBinding(Expression parameter, out Binding binding) 
        { 
            binding = null;
 
            // if there are no binding scopes, their can be no binding
            if (_scopes.Count == 0) { return false; }

            for (int i = _scopes.Count - 1; i >= 0; i--) 
            {
                Binding[] scope = _scopes[i]; 
 
                foreach (Binding scopeBinding in scope)
                { 
                    if (parameter == scopeBinding.LinqExpression)
                    {
                        binding = scopeBinding;
                        return true; 
                    }
                } 
            } 

            // no match found 
            return false;
        }
    }
 
    /// 
    /// Class describing a LINQ parameter and its bound expression. For instance, in 
    /// 
    /// products.Select(p => p.ID)
    /// 
    /// the 'products' query is the bound expression, and 'p' is the parameter.
    /// 
    internal sealed class Binding
    { 
        internal Binding(Expression linqExpression, CqtExpression cqtExpression)
        { 
            LinqExpression = linqExpression; 
            CqtExpression = cqtExpression;
        } 

        internal readonly Expression LinqExpression;
        internal readonly CqtExpression CqtExpression;
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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