如何在列C＃中仅添加数字

Question

I would like to get the total sum of a DataTable column in C#. However, my column consist of both string and numeric values. Is there a way to sum up only numeric values found in the column?

DataTable

Column

hello
304
-312
213
bye

I have tried using the code below but it will not work when there the cell is not in numeric value.

var total = dt.Compute("Sum(column)","");

Answer 1

I don't think you can use casting in Compute so a solution could be something like this (VB.net code):

Dim dt As New DataTable
dt.Columns.Add("test")

dt.Rows.Add("hello")
dt.Rows.Add("304")
dt.Rows.Add("-312")
dt.Rows.Add("213")
dt.Rows.Add("bye")

Dim intTotal As Integer = 0

For Each dr As DataRow In dt.Rows

    Dim intValue As Integer = 0

    If Integer.TryParse(dr("test"), intValue) Then
        intTotal += intValue
    End If

Next dr

MsgBox(intTotal)

Answer 2

decimal sum; for (i=0;i<rows;i++) { sum += decimal.TryParse(dt["Column"][i].ToString(), out var value) ? value : (decimal)0L; }

Answer 3

C# example

Datatable dt = new DataTable()
dt.Columns.Add("test")
dt.Rows.Add("test2")
dt.Rows.Add("45")
dt.Rows.Add("12")
dt.Rows.Add("-213")
dt.Rows.Add("test3")

int total = 0

Foreach(DataRow dr in dt.Rows) {
    If (Integer.TryParse(dr("test")){
        total += dr("test").value)
    }
}

return total;

Answer 4

The Compute method allows type conversion.

var sum = dt.Compute("Sum(Convert(column, 'System.Int32'))");

You can also use LINQ:

int sum = dt.Rows.Select(dr=>(int)dr["column"]).Sum();

For more informations: MSDN