将文本框绑定到数据表列的总和 [英] Bind a TextBox to the Sum of a DataTable Column

问题描述

我想在我的网格下面有一个页脚，以显示有关数据的一些统计信息.

I would like to have a footer under my grid to show some stats about the datas.

例如某些列的总和，另一些列的平均值.

Such as Sum of some columns and average of some other.

我发现有两件事很有趣，可以帮助我做到这一点，将数据框绑定到bindingSource，但是只有选择的行显示在textBox中...

I've found two things intersting to help me do this, binding the databox to a bindingSource, BUT it's only the selected line that is shown into the textBox...

myTextBox.DataBindings.add("Text", myGrid.DataSource,"Weight")

并获取网格中某一列的总和，但是如果我更改网格，它不会更新:S

And getting the Sum of a column in the grid, BUT it doesn't update if I change the grid :S

myTextBox.Text = myGrid.DataSource.DataSource.DataSet.Tables(0).Compute("Sum(Weight)","")

问题

有两种方法都可以吗?

Question

Is there a way to have both?

像BindingSource一样自动更新，而像Compute一样自动求和?

The auto updates as with BindingSource and the Sum as with Compute?

推荐答案

由于您将DataTable用作绑定源，因此只需连接RowChanged事件并在那里计算更改:

Since you are using a DataTable as the binding source, you can just wire the RowChanged event and compute changes there:

Private Sub myTable_RowChanged(ByVal sender As Object, _
                              ByVal e As DataRowChangeEventArgs) _
                              Handles myTable.RowChanged
  myTextBox.Text = myTable.Compute("SUM(Weight)", String.Empty)
End Sub

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