Question

我有一个dataTable与DatagrindView绑定，并希望更新所选列。我的DataTable(displayDT)和我的datagridview1具有相同的布局：

DateTime                  item1            item2            item3
1/1/2010                  100               100              100
1/1/2010 1:00             120               110              90

我有1440条记录。我允许用户按选定列更新数据...因此他们可以选择item1并为每个记录中的值添加一个金额。这是我用来运行更新的代码：

在我的屏幕加载中：

dataGridView1.DataSource = displayDT;
bindingSourceDG.DataSource = displayDT;

这是我的代码，它将使用输入的值更新所选列。

private void btnUpdateColumns_Click(object sender, EventArgs e)
{
    try
    {
        //user will key in a value that they would like 
        //the column to be increased/decreased by
        double iValue = double.Parse(txtValue.Text);  

        this.Cursor = Cursors.WaitCursor;

        //here I am trying to stop the datagridview 
        //from syncing up with the datatable after each record changes.       
        bindingSourceDG.RaiseListChangedEvents = false;

        bindingSourceDG.SuspendBinding();

        //I created a list of columns the user would like 
        //to update by the amount they typed in.
        List<int> colIndexList = new List<int>(dataGridView1.Columns.Count);

        foreach (DataGridViewColumn col in dataGridView1.SelectedColumns)
        {
            colIndexList.Add(col.Index);
        }

        // here is my work around to get this process to work faster....
        //with this line of code(the filter)  the DataTable will 
        //update in a second...
        //without it takes much longer and this is what I 
        //do not understand...????  
        //Why does it update so fast with the filter.  
        //With the filter applied the 1440 record go down 
        //to 24 records.  So try a test with and without this line of code.

        displayDT.DefaultView.RowFilter = 
            "1 = 1 AND DateTime = '" + iModelStartDate + "'";

        //I loop through all the rows in the displayDT and 
        //for each column selected I add the value keyed in by the user.

        foreach (DataRow dr in displayDT.AsEnumerable())
        {
            for (int counter = 0; counter < colIndexList.Count; counter++)
            {
                dr[colIndexList[counter]] = 
                    (double)dr[colIndexList[counter]] + iValue;
            }
        }

        // I clear the filter. 
        //But you would not need this if running without the "work around"
        displayDT.DefaultView.RowFilter = "";

        dataGridView1.CurrentCell = null;

        bindingSourceDG.RaiseListChangedEvents = true;
        bindingSourceDG.ResetBindings(false);

        dataGridView1.Refresh();
    }
    catch
    {
        MessageBox.Show("Please enter numeric value.", "Enter Numeric");
    }

    this.Cursor = Cursors.Default;

}

Answer 1

很好地回答这个问题（我认为......这有点难以理解），过滤器使事情变得更快的原因是因为它减少了处理的记录数量。如你所说：

应用过滤器后，1440记录下降到24条记录

因此，对于过滤器，它只会超过24条记录，而不是整个1440条。

修改

我怀疑它与您使用AsEnumerable（）有关。通常，它与LINQ类型过滤一起使用。我冒昧地猜测，手动设置过滤器可以加快交互速度。我会测试这个hypothisis，但我不会得到时间直到今天晚些时候。

更新绑定到Datagridview的DataTable的性能问题

1 个答案: