private static bool CanBeConvertedAsIsNullComparison(ExpressionMetadata left, FilterComparisonType comparisonType, ExpressionMetadata right)
{
return(right.NodeType == ExpressionMetadataNodeType.Property &&
right.Parameter.Value == null &&
left.NodeType == ExpressionMetadataNodeType.Column &&
(comparisonType == FilterComparisonType.Equal || comparisonType == FilterComparisonType.NotEqual));
}
protected static ExpressionMetadata ApplyNot(ExpressionMetadata expressionMetadata)
{
if (expressionMetadata.NodeType == ExpressionMetadataNodeType.Comparison && NotType.ContainsKey(expressionMetadata.ComparisonType))
{
expressionMetadata.ComparisonType = NotType[expressionMetadata.ComparisonType];
}
return(expressionMetadata);
}
internal static ExpressionMetadata GenerateComparisonExpressionMetadata(ExpressionMetadata left, FilterComparisonType comparisonType, params ExpressionMetadata[] rights)
{
return(new ExpressionMetadata()
{
NodeType = ExpressionMetadataNodeType.Comparison,
LeftExpression = left,
RightExpressions = rights.ToList(),
ComparisonType = comparisonType
});
}
private static ExpressionMetadata GenerateIsNullExpressionMetadata(ExpressionMetadata left,
FilterComparisonType comparisonType)
{
var nullComparisonType = GetNullComparisonType(comparisonType);
return(new ExpressionMetadata()
{
NodeType = ExpressionMetadataNodeType.Comparison,
LeftExpression = left,
ComparisonType = nullComparisonType
});
}