如何在每个类别的末尾添加空数据行

Question

I have DataTable in a C# application.

This DataTable has a column named "Category" and has 10 different values.

This is how my DataTable rows looks like:

How can I add a empty row after each Category group, here is an example of what I need:

Any clue?

Answer 1

Here is the solution that I came up with:

var insertAtIndexes = dataTable.Rows.Cast<DataRow>()
    .GroupBy(row => row["Category"])
    .Select(rowGroup => rowGroup.Select(row => dataTable.Rows.IndexOf(row) + 1)
    .Max()).ToList();

for (var i = 0; i < insertAtIndexes.Count; i++)
{
    var emptyRow = dataTable.NewRow();
    dataTable.Rows.InsertAt(emptyRow, insertAtIndexes[i] + i);
}

This will insert an empty row after each category group (this assumes like in your example that the rows are already ordered by category). We insert in a for loop because as we insert new rows into the table, the insertAtIndexes will need to be increased to account for the newly inserted rows.

NOTE: You can only insert the dataTable.NewRow() if your DataTable columns allow for nulls. If they don't, then do something like this to assign default values. You would't have a blank row because your non-string columns wouldn't allow nulls:

for (var i = 0; i < insertAtIndexes.Count; i++)
{
    var emptyRow = dataTable.NewRow();
    dataTable.Rows.InsertAt(SetDefaultValues(emptyRow), insertAtIndexes[i] + i);
}

static DataRow SetDefaultValues(DataRow row)
{
    row.SetField(1, 0);
    row.SetField(2, 0);
    row.SetField(3, 0);
    row.SetField(4, 0);
    return row;
}

Answer 2

for (int i = dataTable.Rows.Count - 1; i > 0; i--)
{
    if ((string)dataTable.Rows[i]["Category"] != (string)dataTable.Rows[i - 1]["Category"])
    {
        var row = dataTable.NewRow();
        row["Category"] = string.Empty;
        dataTable.Rows.InsertAt(row, i);
    }
}

Answer 3

//Include Two Empty Rows After Each WCG
var insertAtIndexes = ds.Tables["Capacity Progress to Due Date"].Rows.Cast<DataRow>()
//.GroupBy(row => new { wcg = row.Field<int>("WcgName"), Date = Convert.ToDateTime(row.Field<int>("DueDate").ToString()) })
.GroupBy(row => row["WcgName"])
.Select(rowGroup => rowGroup.Select(row => ds.Tables["Capacity Progress to Due Date"].Rows.IndexOf(row) + 1)
.Max()).ToList();

for (var i = 0; i < insertAtIndexes.Count; i++){
    var emptyRow = ds.Tables["Capacity Progress to Due Date"].NewRow();
    var secondemptyRow = ds.Tables["Capacity Progress to Due Date"].NewRow();
    ds.Tables["Capacity Progress to Due Date"].Rows.InsertAt(emptyRow, insertAtIndexes[i] + i + i);
    ds.Tables["Capacity Progress to Due Date"].Rows.InsertAt(secondemptyRow, insertAtIndexes[i] + i + i);
}