/// <summary>
/// 获取表连接时子表的明细数据
/// </summary>
/// <param name="col"></param>
/// <param name="drs"></param>
/// <returns></returns>
private JArray GetChildItems(FieldMeta col, IEnumerable <DataRow> drs)
{
var childModel = _ms.GetTableMeta(col.ArrayItemType);
JArray childDt = new JArray();
//找到ForeignKey定义中的别名
string alias = null;
var aliases = col.ForeignKey.Split('.');
if (aliases.Length > 1)
{
alias = aliases[0];
}
foreach (var dr in drs)
{
var newDr = new JObject();
bool hasValue = false;
foreach (FieldMeta fm in childModel.Fields)
{
var bm = $"{alias ?? childModel.Name}_{fm.Name}";
if (dr[bm] != DBNull.Value)
{
hasValue = true;
}
newDr[fm.Name] = new JValue(dr[bm]);
}
//忽略全部是空的行，这在左连接时经常发生
if (hasValue)
{
childDt.Add(newDr);
}
}
return(childDt);
}
/// <summary>
/// 获取表连接时子表的明细数据，递归执行
/// </summary>
/// <param name="col"></param>
/// <param name="drList"></param>
/// <returns></returns>
private JArray GetChildItems(FieldMeta col, IEnumerable <DataRow> drList)
{
JArray childDt = new JArray();
if (++_deep > 8)
{
return(childDt); //防止递归层次过多
}
if (drList.IsEmpty())
{
return(childDt);
}
var dt = drList.First().Table;
var childTable = _ms.GetTableMeta(col.ArrayItemType);
var pkeys = childTable.PrimaryKeys;
//找到ForeignKey定义中的别名
string alias = null;
var aliases = col.ForeignKey.Split('.');
if (aliases.Length > 1)
{
alias = aliases[0];
}
//当从表的主键字段在数据集中找不到时，说明没有联接此从表
if (pkeys.Any(pkey =>
{
var pkeyAlias = $"{alias ?? childTable.Name}_{pkey.Name}";
return(!dt.Columns.Contains(pkeyAlias));
}))
{
return(childDt);
}
var getPKeyValues = new Func <DataRow, string>(dr =>
{
var keyValues = pkeys.Select(pkey =>
{
var pkeyAlias = $"{alias ?? childTable.Name}_{pkey.Name}";
return(dr[pkeyAlias].ToString());
});
return(String.Join("^", keyValues));
});
//查询主子表中不重复的主键字段值
var keyRowRroups = drList
.GroupBy(dr => getPKeyValues(dr))
.Where(kv => kv.Key.IsNotEmpty()).ToList();
keyRowRroups.Each(drs =>
{
var newRow = new JObject();
//遍历主表的每个字段，找出各类字段定义
childTable.Fields.Each(fm =>
{
var bm = $"{alias ?? childTable.Name}_{fm.Name}";
if (fm.IsArray)
{
newRow[fm.Name] = GetChildItems(fm, drs);
return;
}
else if (fm.DataType == Consts.OperatorUIType)
{
return;
}
if (fm.ForeignField.IsEmpty() && !dt.Columns.Contains(bm))
{
return;
}
var firstDr = drs.First();
newRow[fm.Name] = new JValue(firstDr[bm]);
});
childDt.Add(newRow);
});
_deep--;
return(childDt);
}