public override Expression <Func <TModel, bool> > GetExpression <TModel>(IColumn column, ISearch search, ParameterExpression parameterExpression)
{
var sourcePropertyName = column.Field ?? column.Name;
var sourceProperty = GetProperty <TModel> .ByName(sourcePropertyName);
var sourcePropertyType = sourceProperty.PropertyType;
var sourceNullableType = Nullable.GetUnderlyingType(sourcePropertyType);
Expression property = Expression.Property(parameterExpression, sourceProperty);
bool canBeConvertedToColumnType = TryConvert(search.Value, out TColumn filterValue);
if (canBeConvertedToColumnType)
{
if (TargetType.Equals(sourcePropertyType))
{
Expression valueCheck = Expression.Equal(property, Expression.Constant(filterValue));
return(Expression.Lambda <Func <TModel, bool> >(valueCheck, new ParameterExpression[] { parameterExpression }));
}
else if (TargetType.Equals(sourceNullableType))
{
Expression nullCheck = Expression.NotEqual(property, Expression.Constant(null, sourcePropertyType));
Expression valueCheck = Expression.Equal(property, Expression.Convert(Expression.Constant(filterValue), sourcePropertyType));
//Expression.Lambda
return(Expression.Lambda <Func <TModel, bool> >(Expression.AndAlso(nullCheck, valueCheck), new ParameterExpression[] { parameterExpression }));
}
}
return(null);
}
private IEnumerable <Expression <Func <TModel, object> > > GetSortExpression(IColumn column, ISort sortValue)
{
var sourcePropertyName = column.Field ?? column.Name;
var sourceProperty = GetProperty <TModel> .ByName(sourcePropertyName);
var sourcePropertyType = sourceProperty.PropertyType;
var sourceNullableType = Nullable.GetUnderlyingType(sourcePropertyType);
if (sourceProperty == null)
{
throw new DataTablesException(string.Format(CultureInfo.CurrentUICulture, "Cannot find a Get-property with the name '{0}' on type '{1}'", sourcePropertyName, typeof(TModel).FullName));
}
var expression = Expression.Property(parameterExpression, sourceProperty);
if (sourceNullableType != null)
{
var hasValueExpression = Expression.Convert(Expression.Property(expression, "HasValue"), typeof(object));
var valueExpression = Expression.Convert(Expression.Property(expression, "Value"), typeof(object));
yield return(Expression.Lambda <Func <TModel, object> >(hasValueExpression, new ParameterExpression[] { parameterExpression }));
yield return(Expression.Lambda <Func <TModel, object> >(valueExpression, new ParameterExpression[] { parameterExpression }));
}
else
{
yield return(Expression.Lambda <Func <TModel, object> >(expression, new ParameterExpression[] { parameterExpression }));
}
}
/// <summary>
///
/// </summary>
/// <typeparam name="TModel"></typeparam>
/// <param name="column"></param>
/// <param name="search"></param>
/// <param name="parameterExpression"></param>
/// <returns></returns>
/// <exception cref="NotSupportedException">Thrown when the searchquery is based on an regular expression</exception>
public override Expression <Func <TModel, bool> > GetExpression <TModel>(IColumn column, ISearch search, ParameterExpression parameterExpression)
{
var sourcePropertyName = column.Field ?? column.Name;
var sourceProperty = GetProperty <TModel> .ByName(sourcePropertyName);
var logicalMethod = TargetType.GetMethod(nameof(string.Contains), new[] { typeof(string), typeof(StringComparison) });
var expression = Expression.Call(Expression.Property(parameterExpression, sourceProperty), logicalMethod, Expression.Constant(search.Value), Expression.Constant(StringComparison.CurrentCultureIgnoreCase));
return(Expression.Lambda <Func <TModel, bool> >(expression, new ParameterExpression[] { parameterExpression }));
}
public virtual void ValidateCreateExpressionCall <TModel>(IColumn column, ISearch search, ParameterExpression parameterExpression)
{
if (search.IsRegex && SupportsReqularExpressions == false)
{
throw new NotSupportedException($"The expression creator {this.GetType().FullName} does not support regular expressions.");
}
var sourcePropertyName = column.Field ?? column.Name;
var sourceProperty = GetProperty <TModel> .ByName(sourcePropertyName);
if (sourceProperty == null)
{
throw new ArgumentOutOfRangeException(nameof(column), $"The column '{sourcePropertyName}' is not a property of the model '{typeof(TModel).FullName}'");
}
}
private Expression <Func <TModel, bool> > GetFilterExpression(IColumn column, ISearch search, IEnumerable <IPropertyExpressionCreator> propertyExpressionCreators)
{
var sourcePropertyName = column.Field ?? column.Name;
var sourceProperty = GetProperty <TModel> .ByName(sourcePropertyName);
if (sourceProperty == null)
{
throw new DataTablesException(string.Format(CultureInfo.CurrentUICulture, "Cannot find a Get-property with the name '{0}' on type '{1}'", sourcePropertyName, typeof(TModel).FullName));
}
var sourcePropertyType = sourceProperty.PropertyType;
var sourceNullableType = Nullable.GetUnderlyingType(sourcePropertyType);
var expressionCreator = propertyExpressionCreators.FirstOrDefault(creator => creator.TargetType.Equals(sourcePropertyType) ||
creator.TargetType.Equals(sourceNullableType));
if (expressionCreator == null)
{
throw new DataTablesException(string.Format(CultureInfo.CurrentUICulture, "Cannot find an Expression Creator for type '{0}'", sourceProperty.PropertyType.FullName));
}
return(expressionCreator.CreateExpression <TModel>(column, search, parameterExpression));
}
