Remove all columns with no data from DataTable
If all the items for a particular column are empty, I want to remove that column from the DataTable. What's the most elegant way to do this operation on all columns in t开发者_运维百科he DataTable?
You can use the Compute
method, like this:
if (table.Compute("COUNT(ColumnName)", "ColumnName <> NULL") == 0)
table.Columns.Remove("ColumnName");
Alternatively, you can use LINQ:
if (table.AsEnumerable().All(dr => dr.IsNull("ColumnName")))
table.Columns.Remove("ColumnName");
EDIT: To completely answer the question:
foreach(var column in table.Columns.Cast<DataColumn>().ToArray()) {
if (table.AsEnumerable().All(dr => dr.IsNull(column)))
table.Columns.Remove(column);
}
You need to call ToArray
because the loop will modify the collection.
private static void RemoveUnusedColumnsAndRows(DataTable table)
{
for (int h = 0; h < table.Rows.Count; h++)
{
if (table.Rows[h].IsNull(0) == true)
{
table.Rows[h].Delete();
}
enter code here
}
table.AcceptChanges();
foreach (var column in table.Columns.Cast<DataColumn>().ToArray())
{
if (table.AsEnumerable().All(dr => dr.IsNull(column)))
table.Columns.Remove(column);
}
table.AcceptChanges();
}
public static void RemoveNullColumnFromDataTable(DataTable dt)
{
for (int i = dt.Rows.Count - 1; i >= 0; i--)
{
if (dt.Rows[i][1] == DBNull.Value)
dt.Rows[i].Delete();
}
dt.AcceptChanges();
}
Function RemoveEmptyColumns(Datatable As DataTable) As Boolean
Dim mynetable As DataTable = Datatable.Copy
Dim counter As Integer = mynetable.Rows.Count
Dim col As DataColumn
For Each col In mynetable.Columns
Dim dr() As DataRow = mynetable.Select(col.ColumnName + " is Null ")
If dr.Length = counter Then
Datatable.Columns.Remove(col.ColumnName)
Datatable.AcceptChanges()
End If
return true
end function
You clear all column in datatable.you use like that.
datatable.Columns.Clear();
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