/// <summary>
/// list 转换为 PagingDataSource
/// </summary>
/// <returns></returns>
private static PagingDataSource <T> ToPagingDataSource <T>(this IList <T> dataSource,
OrderPagingQuery <T> orderPagingQuery, int recordCount = 0) where T : class
{
var pagingData = new PagingDataSource <T>(dataSource, orderPagingQuery.Page, orderPagingQuery.PageSize,
recordCount);
pagingData.OrderFieldStore = orderPagingQuery.OrderFieldStore;
return(pagingData);
}
public static string BuildPageSql <T>(string withSql, OrderPagingQuery <T> query, string tableName = "TResult") where T : class
{
var sqlCommand = new StringBuilder();
sqlCommand.Append(withSql);
sqlCommand.Append("SELECT ");
sqlCommand.Append("*");
sqlCommand.Append(" FROM (SELECT ROW_NUMBER() OVER(");
StringBuilder orderFileds = BuildOrderField(query.OrderFieldStore);
sqlCommand.Append(orderFileds);
sqlCommand.Append(") AS ROW_NUMBER,");
sqlCommand.Append("*");
sqlCommand.Append(" FROM ");
sqlCommand.Append(tableName);
sqlCommand.Append(") AS T0 WHERE ROW_NUMBER BETWEEN ");
sqlCommand.Append((((query.Page - 1) * query.PageSize) + 1).ToString());
sqlCommand.Append(" AND ");
sqlCommand.Append((query.Page * query.PageSize).ToString());
return(sqlCommand.ToString());
}
/// <summary>
/// 获取排序并分页的数据 如果有排序条件 会覆盖已有的排序条件
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryableSource"></param>
/// <param name="pagingQuery"></param>
/// <param name="recordCount"></param>
/// <returns></returns>
public static PagingDataSource <T> QueryPagingDataSource <T>(this IQueryable <T> queryableSource, OrderPagingQuery <T> pagingQuery, int recordCount = 0) where T : class
{
if (recordCount == 0 && pagingQuery.IsGetRecordCount)
{
recordCount = queryableSource.Count();
}
bool ordered = false;
foreach (OrderField <T> orderField in pagingQuery.OrderFieldStore.OrderFields)
{
string orderType = string.Empty;
if (orderField.OrderType == OrderType.Descending)
{
orderType = ordered ? "ThenByDescending" : "OrderByDescending";
}
else if (orderField.OrderType == OrderType.Ascending)
{
orderType = ordered ? "ThenBy" : "OrderBy";
}
if (!string.IsNullOrEmpty(orderType))
{
Expression sortExpression = Unbox(orderField.MemberExpression.Body);
Type sortType = sortExpression.Type;//排序字段的实际类型
Type funType = typeof(Func <,>);
funType = funType.MakeGenericType(typeof(T), sortType);
LambdaExpression lambda = Expression.Lambda(funType, sortExpression,
orderField.MemberExpression.Parameters);
MethodCallExpression method = Expression.Call(typeof(Queryable), orderType,
new Type[] { typeof(T), sortExpression.Type },
queryableSource.Expression, lambda);
queryableSource = queryableSource.Provider.CreateQuery <T>(method);
ordered = true;
}
}
return
(ToPagingDataSource(queryableSource.Skip(pagingQuery.GetSkipCount()).Take(pagingQuery.PageSize).ToList(),
pagingQuery, recordCount));
}
/// <summary>
/// 对list进行排序和分页
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="listSource"></param>
/// <param name="pagingQuery"></param>
/// <param name="recordCount"></param>
/// <returns></returns>
public static PagingDataSource <T> ListPagingDataSource <T>(this IList <T> listSource, OrderPagingQuery <T> pagingQuery, int recordCount = 0) where T : class
{
if (recordCount == 0 && pagingQuery.IsGetRecordCount)
{
recordCount = listSource.Count();
}
IOrderedEnumerable <T> query = null;
foreach (OrderField <T> orderField in pagingQuery.OrderFieldStore.OrderFields)
{
if (orderField.OrderType != OrderType.None)
{
if (query != null)
{
if (orderField.OrderType == OrderType.Ascending)
{
query = query.ThenBy(orderField.MemberExpression.Compile());
}
if (orderField.OrderType == OrderType.Descending)
{
query = query.ThenByDescending(orderField.MemberExpression.Compile());
}
}
else
{
if (orderField.OrderType == OrderType.Ascending)
{
query = listSource.OrderBy(orderField.MemberExpression.Compile());
}
if (orderField.OrderType == OrderType.Descending)
{
query = listSource.OrderByDescending(orderField.MemberExpression.Compile());
}
}
}
}
return
(ToPagingDataSource(query.Skip(pagingQuery.GetSkipCount()).Take(pagingQuery.PageSize).ToList(),
pagingQuery, recordCount));
}
