如何在动态生成的GridView中处理文本框的TextChanged事件？

Question

我动态生成了GridView。它具有使用文本框模板创建的列。用于创建文本框模板的类如下：

public class GridViewTextboxTemplate : ITemplate
{
    private DataControlRowType templateType;
    private string columnName;
    private string dataType;
    frmPracticalMarksEntry _PME;

    public GridViewTextboxTemplate(DataControlRowType type,
        string colname, string DataType, frmPracticalMarksEntry PME)
    {
        templateType = type;
        columnName = colname;
        dataType = DataType;
        _PME = PME;
    }
    public void InstantiateIn(System.Web.UI.Control container)
    {
        DataControlFieldCell hc = null;

        switch (templateType)
        {
            case DataControlRowType.Header:
                // build the header for this column
                Literal lc = new Literal();
                lc.Text = columnName;
                container.Controls.Add(lc);
                break;
            case DataControlRowType.DataRow:
                // build one row in this column
                TextBox l = new TextBox();

                // register an event handler to perform the data binding
                l.DataBinding += new EventHandler(this.txt_DataBinding);
                l.TextChanged += new EventHandler(this.txt_TextChanged);

                l.AutoPostBack = true;

                container.Controls.Add(l);
                break;
            default:
                break;
        }
    }

    private void txt_DataBinding(Object sender, EventArgs e)
    {
        // get the control that raised this event
        TextBox l = (TextBox)sender;
        // get the containing row
        GridViewRow row = (GridViewRow)l.NamingContainer;
        // get the raw data value and make it pretty
        string RawValue = DataBinder.Eval(row.DataItem, columnName).ToString();
        l.Text = RawValue;
    }
    private void txt_TextChanged(Object sender, EventArgs e)
    {
        _PME.lblEr.Text = (sender as TextBox).Text;
    }
}

现在，只要文本框值发生变化，我就需要处理TextChanged事件。 因此，我添加了事件处理程序txt_TextChanged来处理文本更改事件。

如果我在回发期间发生don't rebind the GridView again in Page_Load事件，则会发生doesn't retain its state。

所以我需要再次绑定它。

现在，txt_TextChanged事件将触发已更改值的每个文本框。但是应该仅针对其值刚刚更改的文本框触发。因此，它返回网格中最后一个非空白文本框的值。