Question

winform中如何对一个 datatable 中的数据 进行 分组统计 需要 count 和group by

winform中如何对一个 datatable 中的数据 进行 分组统计 需要 count 和group by

Answer 1

1 一种方式是借用linq
2 自己写代码处理
a 分组排序

public static void GroupByDT(ref DataTable dt,string strColumName,string strSortColumnName)
{
if (dt == null && dt.Rows.Count == 0){}
else
{
DataTable dtResult = dt.Clone();
DataTable dtSortResult = dt.Clone();
if(dt.Rows.Count == 1)
{
dtResult.ImportRow(dt.Rows[0]);
}
else
{
dtSortResult = SortDT(dt, strSortColumnName);
for (int i = 0; i < dtSortResult.Rows.Count; i++)
{
for (int j = dtSortResult.Rows.Count-1; j >= 0; j--)
{
if(dtSortResult.Rows.Count > 0)
{
if (dtSortResult.Rows[i][strColumName] == dtSortResult.Rows[j][strColumName])
{
string strPrjID = dtSortResult.Rows[j][strColumName].ToString();
dtResult.ImportRow(dtSortResult.Rows[j]);
dtSortResult.Rows.Remove(dtSortResult.Rows[j]);
if (i != 0) { i--; } else { }
if (j != dtSortResult.Rows.Count) { j++; }
else if (j == 0) { j++; }
}
}
}
}
dt.Clear();
dt.Merge(dtResult);
}
}
}
b count 汇总计算

public static DataTable CalculateSumInfo(DataTable dt)
{
DataTable dtResult = dt.Copy();
object objsumDebit = dtResult.Compute("sum(Debit)", "TRUE");
object objsumCredit = dtResult.Compute("sum(Credit)", "TRUE");
decimal surplusFund = Math.Round((Convert.ToDecimal(objsumDebit) - Convert.ToDecimal(objsumCredit)), 2);
DataRow row = dtResult.NewRow();
row["SurplusFund"] = surplusFund;
dtResult.Rows.Add(row);
return dtResult;
}

Answer 2

linq to datatable