Question

在GridView的asp：TemplateField列中，我有一个LinkButton，它将一个命令参数传递给一个函数，该函数在单击时删除该行。但是，在对GridView进行排序后，LinkButton会传递错误的参数。此外，GridView丢失了排序顺序。

我做错了什么？

这是我的代码：

<!---master page---->
<asp:GridView runat="server" ID="companies_grid" AllowSorting="true"
    AutoGenerateColumns="false" OnSorting="companies_grid_OnSorting"
    OnRowDataBound="companies_grid_OnRowDataBound" >
        <Columns>
            <%--Company Name--%>
            <asp:TemplateField HeaderText="Company Name" SortExpression="Name">
                <ItemTemplate>
                    <asp:LinkButton ID="LinkButton1" runat="server"
                         OnClick="removeCompany_click" />
                     <a href='<%#Eval("URL")%>'><%#Eval("Name")%></a>
                </ItemTemplate>
             </asp:TemplateField>
            //more columns

<!---code behind---->
    protected void Page_Load(object sender, EventArgs e)
    {
        companies = GetCompanyData();

        companies_grid.DataSource = companies;
        companies_grid.DataBind();
    }

    protected void companies_grid_OnSorting(object sender, GridViewSortEventArgs e)
    {
        //sort is made up of column to sort by + direction
        companies.DefaultView.Sort = e.SortExpression.ToString() + " " + GetSortDirection(e.SortExpression, "companiesExpression", "companiesDirection");
        companies_grid.DataSource = companies;
        companies_grid.DataBind();

    }

    private string GetSortDirection(string column, string expressionViewState, string directionViewState)
    {
        // By default, set the sort direction to ascending.
        string sortDirection = "ASC";

        // Retrieve the last column that was sorted.
        string sortExpression = ViewState[expressionViewState] as string;

        if (sortExpression != null)
        {
            // Check if the same column is being sorted.
            // Otherwise, the default value can be returned.
            if (sortExpression == column)
            {
                string lastDirection = ViewState[directionViewState] as string;
                if ((lastDirection != null) && (lastDirection == "ASC"))
                {
                    sortDirection = "DESC";
                }
            }
        }

        // Save new values in ViewState.
        ViewState[directionViewState] = sortDirection;
        ViewState[expressionViewState] = column;

        return sortDirection;
    }

    protected void companies_grid_OnRowDataBound(Object Sender, GridViewRowEventArgs e)
    {
        GridViewRow currRow = e.Row;

        if (currRow.RowType == DataControlRowType.DataRow)
        {
            LinkButton deleteCompButton = (LinkButton)e.Row.FindControl("LinkButton1") as LinkButton;
            deleteCompButton.CommandArgument = ((DataRowView)e.Row.DataItem)["Company_ID"].ToString();
            deleteCompButton.Text = ((DataRowView)e.Row.DataItem)["Company_ID"].ToString();
        }
    }

    protected void removeCompany_click(Object sender, EventArgs e)
    {
        bool removeSuccess = false;

        string idToDelete = ((LinkButton)sender).CommandArgument as string;
        removeSuccess = UserInfo.DeleteCompany(idToDelete);
        if (removeSuccess)
        {
            Response.Redirect(Request.RawUrl);
        }
    }

Answer 1

问题在于：

单击LinkButton时，首先发生的是页面重新加载。但是，Response.Redirect(Request.RawUrl)不保留ViewState，因此排序顺序丢失。因此，GridView将使用未排序的数据重新填充。

然后，调用LinkButton onClick事件函数。传入的Object是来自正确行号的LinkButton，但由于表的排序顺序已更改（返回其未排序状态），该行中的LinkButton不再是用户单击的LinkButton。因此，命令参数是错误的。

解决问题：

我将所有ViewState [string]更改为Session [string]（以便在页面重新加载时保留排序方向），并在GridView绑定之前在Page_Load函数中添加以下代码：

if (Session["companiesExpression"] != null 
     && Session["companiesDirection"] != null)
{
     companies.DefaultView.Sort = Session["companiesExpression"] + " " +
          Session["companiesDirection"];
 }

排序gridview后错误的linkbutton命令参数

1 个答案: