/// <summary>
/// Initializes a new instance of the FilterBuildingExpressionVisitor
/// class.
/// </summary>
/// <param name="contractResolver">
/// The contract resolver to use to determine property
/// names from members used within expressions.
/// </param>
private FilterBuildingExpressionVisitor(MobileServiceContractResolver contractResolver)
: base()
{
Debug.Assert(contractResolver != null);
this.contractResolver = contractResolver;
}
/// <summary>
/// Translate an expression tree into a compiled OData query.
/// </summary>
/// <param name="expression">
/// The expression tree.
/// </param>
/// <param name="contractResolver">
/// The contract resolver used to determine property names from
/// members used within expressions.
/// </param>
/// <returns>
/// An OData query.
/// </returns>
public static string Create(Expression expression, MobileServiceContractResolver contractResolver)
{
Debug.Assert(expression != null);
Debug.Assert(contractResolver != null);
// Walk the expression tree and build the filter.
FilterBuildingExpressionVisitor visitor = new FilterBuildingExpressionVisitor(contractResolver);
visitor.Visit(expression);
return(visitor.filter.ToString());
}
/// <summary>
/// Get the table member name referenced by an expression or return null.
/// </summary>
/// <param name="expression">
/// The expression to check.
/// </param>
/// <param name="contractResolver">
/// The contract resolver to use to determine property names from members used
/// within expressions.
/// </param>
/// <returns>
/// The table member name or null.
/// </returns>
public static string GetTableMemberName(Expression expression,
MobileServiceContractResolver contractResolver)
{
Debug.Assert(expression != null);
Debug.Assert(contractResolver != null);
// Only parameter references are valid in a query (any other
// references should have been partially evaluated away)
MemberExpression member = expression as MemberExpression;
if (member != null &&
member.Expression != null &&
member.Expression.NodeType == ExpressionType.Parameter &&
member.Member != null)
{
// Lookup the Mobile Services name of the member and use that
JsonProperty property = contractResolver.ResolveProperty(member.Member);
return(property.PropertyName);
}
// Otherwise return null
return(null);
}
/// <summary>
/// Get the table member name referenced by an expression or return null.
/// </summary>
/// <param name="expression">
/// The expression to check.
/// </param>
/// <param name="contractResolver">
/// The contract resolver to use to determine property names from members used
/// within expressions.
/// </param>
/// <returns>
/// The table member name or null.
/// </returns>
public static string GetTableMemberName(Expression expression,
MobileServiceContractResolver contractResolver)
{
Debug.Assert(expression != null);
Debug.Assert(contractResolver != null);
// Only parameter references are valid in a query (any other
// references should have been partially evaluated away)
MemberExpression member = expression as MemberExpression;
if (member != null &&
member.Expression != null &&
member.Expression.NodeType == ExpressionType.Parameter &&
member.Member != null)
{
// Lookup the Mobile Services name of the member and use that
JsonProperty property = contractResolver.ResolveProperty(member.Member);
return property.PropertyName;
}
// Otherwise return null
return null;
}
/// <summary>
/// Translate an expression tree into a compiled OData query.
/// </summary>
/// <param name="expression">
/// The expression tree.
/// </param>
/// <param name="contractResolver">
/// The contract resolver used to determine property names from
/// members used within expressions.
/// </param>
/// <returns>
/// An OData query.
/// </returns>
public static string Create(Expression expression, MobileServiceContractResolver contractResolver)
{
Debug.Assert(expression != null);
Debug.Assert(contractResolver != null);
// Walk the expression tree and build the filter.
FilterBuildingExpressionVisitor visitor = new FilterBuildingExpressionVisitor(contractResolver);
visitor.Visit(expression);
return visitor.filter.ToString();
}
/// <summary>
/// Initializes a new instance of the FilterBuildingExpressionVisitor
/// class.
/// </summary>
/// <param name="contractResolver">
/// The contract resolver to use to determine property
/// names from members used within expressions.
/// </param>
private FilterBuildingExpressionVisitor(MobileServiceContractResolver contractResolver)
: base()
{
Debug.Assert(contractResolver != null);
this.contractResolver = contractResolver;
}
