动态PIVOT使用C＃Linq [英] Dynamic PIVOT using C# Linq
本文介绍了动态PIVOT使用C＃Linq的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图使用下面的代码创建PIVOT，但它不工作。
I am trying to use following code to create the PIVOT but its not working.
这给我编译时错误。我不知道linq因此无法使用它。
It's giving me compile time error. I don't know linq so unable to use it.
请帮助：
DataTable Pivot(DataTable dt, DataColumn pivotColumn, DataColumn pivotValue) {
// find primary key columns
//(i.e. everything but pivot column and pivot value)
DataTable temp = dt.Copy();
temp.Columns.Remove( pivotColumn.ColumnName );
temp.Columns.Remove( pivotValue.ColumnName );
string[] pkColumnNames = temp.Columns.Cast(<DataColumn>)
.Select( c => c.ColumnName )
.ToArray();
// prep results table
DataTable result = temp.DefaultView.ToTable(true, pkColumnNames).Copy();
result.PrimaryKey = result.Columns.Cast(<DataColumn>).ToArray();
dt.AsEnumerable()
.Select(r =>; r[pivotColumn.ColumnName].ToString())
.Distinct().ToList()
.ForEach (c => result.Columns.Add(c, pivotColumn.DataType));
// load it
foreach( DataRow row in dt.Rows ) {
// find row to update
DataRow aggRow = result.Rows.Find(
pkColumnNames
.Select( c => row[c] )
.ToArray() );
// the aggregate used here is LATEST
// adjust the next line if you want (SUM, MAX, etc...)
aggRow[row[pivotColumn.ColumnName].ToString()] = row[pivotValue.ColumnName];
}
return result;
}
代码： http://michaeljswart.com/2011/06/forget-about-pivot/
此外，它试图使用下面的代码，它工作得很好，除了它不是值列的总和
Moreover it tried to use following code, it works well except for it is not giving total sum for Value Column
public DataTable GetInversedDataTable(DataTable table, string columnX, string columnY, string columnZ, string nullValue, bool sumValues)
{
//Create a DataTable to Return
DataTable returnTable = new DataTable();
DataTable tempTable = table.Clone();
if (string.IsNullOrEmpty(columnX))
{
columnX = table.Columns[0].ColumnName;
}
tempTable.Columns.Remove(columnX);
//Add a Column at the beginning of the table
//returnTable.Columns.Add(columnY);
returnTable = tempTable.Clone();
//Read all DISTINCT values from columnX Column in the provided DataTale
List<string> columnXValues = new List<string>();
foreach (DataRow dr in table.Rows)
{
string columnXTemp = dr[columnX].ToString();
if (!columnXValues.Contains(columnXTemp))
{
//Read each row value, if it's different from others provided, add to the list of values and creates a new Column with its value.
columnXValues.Add(columnXTemp);
returnTable.Columns.Add(columnXTemp);
}
}
//Verify if Y and Z Axis columns re provided
if (!string.IsNullOrEmpty(columnY) && !string.IsNullOrEmpty(columnZ))
{
//Read DISTINCT Values for Y Axis Column
List<string> columnYValues = new List<string>();
foreach (DataRow dr in table.Rows)
{
if (!columnYValues.Contains(dr[columnY].ToString()))
{
columnYValues.Add(dr[columnY].ToString());
}
}
//Loop all Column Y Distinct Value
foreach (string columnYValue in columnYValues)
{
//Creates a new Row
DataRow drReturn = returnTable.NewRow();
drReturn[0] = columnYValue;
//foreach column Y value, The rows are selected distincted
DataRow[] rows = table.Select((columnY + "='") + columnYValue + "'");
//Read each row to fill the DataTable
foreach (DataRow dr in rows)
{
string rowColumnTitle = dr[columnX].ToString();
//Read each column to fill the DataTable
foreach (DataColumn dc in returnTable.Columns)
{
if (dc.ColumnName == rowColumnTitle)
{
//If Sum of Values is True it try to perform a Sum
//If sum is not possible due to value types, the value displayed is the last one read
if (sumValues)
{
try
{
drReturn[rowColumnTitle] = Convert.ToDecimal(drReturn[rowColumnTitle]) + Convert.ToDecimal(dr[columnZ]);
}
catch
{
drReturn[rowColumnTitle] = dr[columnZ];
}
}
else
{
drReturn[rowColumnTitle] = dr[columnZ];
}
}
}
}
returnTable.Rows.Add(drReturn);
}
}
else
{
throw new Exception("The columns to perform inversion are not provided");
}
//if a nullValue is provided, fill the datable with it
if (!string.IsNullOrEmpty(nullValue))
{
foreach (DataRow dr in returnTable.Rows)
{
foreach (DataColumn dc in returnTable.Columns)
{
if (string.IsNullOrEmpty(dr[dc.ColumnName].ToString()))
{
dr[dc.ColumnName] = nullValue;
}
}
}
}
return returnTable;
}
GetInversedDataTable(dtNormal, "Dated", "OrderStatus", "Qty", " ", true);
请帮助：）
推荐答案
下面是修正编译错误的代码：
Here is the code with the compilation errors corrected:
DataTable Pivot(DataTable dt, DataColumn pivotColumn, DataColumn pivotValue) {
// find primary key columns
//(i.e. everything but pivot column and pivot value)
DataTable temp = dt.Copy();
temp.Columns.Remove( pivotColumn.ColumnName );
temp.Columns.Remove( pivotValue.ColumnName );
string[] pkColumnNames = temp.Columns.Cast<DataColumn>()
.Select( c => c.ColumnName )
.ToArray();
// prep results table
DataTable result = temp.DefaultView.ToTable(true, pkColumnNames).Copy();
result.PrimaryKey = result.Columns.Cast<DataColumn>().ToArray();
dt.AsEnumerable()
.Select(r => r[pivotColumn.ColumnName].ToString())
.Distinct().ToList()
.ForEach (c => result.Columns.Add(c, pivotColumn.DataType));
// load it
foreach( DataRow row in dt.Rows ) {
// find row to update
DataRow aggRow = result.Rows.Find(
pkColumnNames
.Select( c => row[c] )
.ToArray() );
// the aggregate used here is LATEST
// adjust the next line if you want (SUM, MAX, etc...)
aggRow[row[pivotColumn.ColumnName].ToString()] = row[pivotValue.ColumnName];
}
return result;
}
我更改了 Cast（< DataColumn>）到在两个位置处转换< DataColumn>（），并摆脱了lambda表达式中间的分号。你的问题的第二部分有点棘手。您可以将其作为自己的问题。
I changed Cast(<DataColumn>) to Cast<DataColumn>() in two locations and got rid of the semicolon in the middle of a lambda expression. The second part of your question is a little trickier. You may want to ask it as its own question.
这篇关于动态PIVOT使用C＃Linq的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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