为什么我得到GridViewUpdateEventArgs#NewValues和GridViewUpdateEventA

本文关键字：GridViewUpdateEventA GridViewUpdateEventArgs#NewValues 为什么 | 更新日期: 2023-09-27 18:01:36

我将GridView绑定为-

namespace grid_edit
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection();
            con.ConnectionString = "Data source=HP_OWNER''SQLEXPRESS;Database=demo;Integrated security=true";
            con.Open();
            SqlCommand cmd = new SqlCommand("select * from demo", con);
            cmd.ExecuteNonQuery();
            SqlDataAdapter mySqlAdapter = new SqlDataAdapter(cmd);
            DataSet myDataSet = new DataSet();
            mySqlAdapter.Fill(myDataSet);
            DataTable myDataTable = myDataSet.Tables[0];
            GridView1.DataSource = myDataTable;
            GridView1.DataBind();
            Session["mytable"] = myDataTable;

        }
        protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
        {
            GridView1.EditIndex = e.NewEditIndex;
            GridView1.DataBind();
        }       
        protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            String updatedItem = e.NewValues[0].ToString();
            String anotherUpdatedItem = e.NewValues[1].ToString();
        }
    }
}

<asp:GridView ID="GridView1" runat="server" AutoGenerateEditButton="True" 
            BackColor="#CCCCCC" BorderColor="#999999" BorderStyle="Solid" BorderWidth="3px" 
            CellPadding="4" CellSpacing="2" ForeColor="Black"            
        style="top: 63px; left: 309px; position: absolute; height: 183px; width: 312px; margin-top: 25px;" 
        OnRowEditing="GridView1_RowEditing" 
        OnRowCancelingEdit="GridView1_RowCancelingEdit"        
        OnRowUpdating="GridView1_RowUpdating" >
            <RowStyle BackColor="White" />
            <FooterStyle BackColor="#CCCCCC" />
            <PagerStyle BackColor="#CCCCCC" ForeColor="Black" HorizontalAlign="Left" />
            <SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
            <HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
        </asp:GridView>

现在我想从网格视图更新行，但在更新事件GridViewUpdateEventArgs我得到NewValues和OldValues空。
我怎样才能得到更新的值存储在数据库中?我做错了什么吗?

为什么我得到GridViewUpdateEventArgs#NewValues和GridViewUpdateEventA

尝试按如下方式更改代码:

protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection();
        con.ConnectionString = "Data source=(local);Database=northwind;Integrated security=true";
        con.Open();
        SqlCommand cmd = new SqlCommand("select * from Categories", con);
        cmd.ExecuteNonQuery();
        SqlDataAdapter mySqlAdapter = new SqlDataAdapter(cmd);
        DataSet myDataSet = new DataSet();
        mySqlAdapter.Fill(myDataSet);
        DataTable myDataTable = myDataSet.Tables[0];
        GridView1.DataSource = myDataTable;
    if(!IsPostBack)  /// <<<<<<<<<<<<<<<<<<<<<<
        GridView1.DataBind();
        Session["mytable"] = myDataTable;
    }

在。net Framework 4中可以正常工作。

因为你使用的是。net Framework 3.0，所以这段代码不能工作。我看了GridView的HandleUpdate方法，发现这些集合(e.NewValues和e.OldValues)只有在GridView通过DataSourceID属性绑定到DataSourceControl时才会填充…一个可能的解决方案是使用ExtractValuesFromCell方法:

    cell = GridView1.Rows[e.RowIndex].Cells[1] as DataControlFieldCell;
    GridView1.Columns[1].ExtractValuesFromCell(
        e.NewValues,
        cell,
        DataControlRowState.Edit,
        true);

注意:Page_Load方法应该有我建议的代码，即DataBind应该只调用一次。