public void UpdatePartial <T>(Expression <Func <T> > columns)
{
Table tableOrCreate = TableCache.GetTableOrCreate(typeof(T));
Dictionary <Column, object> tempDict = new Dictionary <Column, object>();
MemberInitExpression body = columns.Body as MemberInitExpression;
if (body == null)
{
throw new ApplicationException("部分更新只支持对象初始化的方式");
}
foreach (MemberBinding binding in body.Bindings)
{
if (binding.BindingType != MemberBindingType.Assignment)
{
throw new ApplicationException("暂不支持复杂的属性初始化方式");
}
MemberAssignment assignment = binding as MemberAssignment;
ConstantExpression expression2 = PartialEvaluator.Eval(assignment.Expression) as ConstantExpression;
string name = assignment.Member.Name;
if (expression2 == null)
{
throw new ApplicationException(string.Format("无法计算属性{0}的值", name));
}
object obj2 = expression2.Value;
Column columnByColumnName = tableOrCreate.GetColumnByColumnName(name);
if (columnByColumnName == null)
{
throw new ApplicationException(string.Format("在表{0}中找不到名为{1}的列", tableOrCreate.TableName, name));
}
tempDict[columnByColumnName] = obj2;
Trace.WriteLine(string.Format("{0}-{1}", name, obj2));
}
Dictionary <Column, object> keyDict = tableOrCreate.KeyColumns.ToDictionary <Column, Column, object>(p => p, delegate(Column p) {
if (!tempDict.ContainsKey(p))
{
throw new ApplicationException(string.Format("未给主键字段{0}赋值", p.ColumnName));
}
return(tempDict[p]);
});
Dictionary <Column, object> valueDict = (from p in tempDict
where !p.Key.IsPrimaryKey
select p).ToDictionary <KeyValuePair <Column, object>, Column, object>(p => p.Key, p => p.Value);
this.InternalUpdatePartial(typeof(T), keyDict, valueDict);
}
private LambdaExpression Parameterize(Expression query, out object[] arguments)
{
IQueryProvider provider = this.FindProvider(query);
if (provider == null)
{
throw new ArgumentException("Cannot deduce query provider from query");
}
IEntityProvider ep = provider as IEntityProvider;
Func <Expression, bool> fnCanBeEvaluated = (ep != null) ? new Func <Expression, bool>(ep.CanBeEvaluatedLocally) : null;
List <ParameterExpression> parameters = new List <ParameterExpression>();
List <object> values = new List <object>();
Expression expression = PartialEvaluator.Eval(query, fnCanBeEvaluated, delegate(ConstantExpression c) {
bool flag = c.Value is IQueryable;
if (!((flag || (ep == null)) || ep.CanBeParameter(c)))
{
return(c);
}
ParameterExpression item = Expression.Parameter(c.Type, "p" + parameters.Count);
parameters.Add(item);
values.Add(c.Value);
if (flag)
{
return(c);
}
return(item);
});
if (expression.Type != typeof(object))
{
expression = Expression.Convert(expression, typeof(object));
}
arguments = values.ToArray();
if (arguments.Length < 5)
{
return(Expression.Lambda(expression, parameters.ToArray()));
}
arguments = new object[] { arguments };
return(ExplicitToObjectArray.Rewrite(expression, parameters));
}
internal IQueryProvider FindProvider(Expression expression, object[] args)
{
Func <object, int, ConstantExpression> selector = null;
Expression expression2 = this.FindProviderInExpression(expression) as ConstantExpression;
if (((expression2 == null) && (args != null)) && (args.Length > 0))
{
if (selector == null)
{
selector = (a, i) => Expression.Constant(a, this.query.Parameters[i].Type);
}
Expression expression3 = ExpressionReplacer.ReplaceAll(expression, this.query.Parameters.ToArray <ParameterExpression>(), args.Select <object, ConstantExpression>(selector).ToArray <ConstantExpression>());
expression2 = this.FindProviderInExpression(expression3);
}
if (expression2 != null)
{
ConstantExpression expression4 = expression2 as ConstantExpression;
if (expression4 == null)
{
expression4 = PartialEvaluator.Eval(expression2) as ConstantExpression;
}
if (expression4 != null)
{
IQueryProvider provider = expression4.Value as IQueryProvider;
if (provider == null)
{
IQueryable queryable = expression4.Value as IQueryable;
if (queryable != null)
{
provider = queryable.Provider;
}
}
return(provider);
}
}
return(null);
}