Gridview中的编辑命令

Question

我从gridview中的数据库中提取数据，其中我已经给出了用于编辑该行数据的链接按钮“编辑”。然而，在编辑时，我的gridview的其中一列（YEAR）成为下拉列表。在从数据库中提取数据时，“年份”列由标签组成，在编辑模式下，它变为下拉列表。此外，我添加了一个条件，使链接按钮出现/消失根据标签“年”的值。当我编辑特定行时，它会引发错误，因为一旦调用编辑命令，它会将列转换为下拉列表，但是row_databound会搜索标签。它显示“对象未设置为一个实例.....”请帮

.aspx的

<asp:GridView ID="gv1" runat="server" AutoGenerateColumns="False" BackColor="White" BorderColor="#3366CC" BorderStyle="None" BorderWidth="1px" CellPadding="4" DataSourceID="SqlDataSource2" OnRowDataBound="gv1_RowDataBound" OnRowUpdating="gv1_RowUpdating" DataKeyNames="tid" CssClass="auto-style1" Width="694px"> 
     <Columns> 
      <asp:TemplateField HeaderText="Sr No"> 
       <ItemTemplate> 
        <%#Container.DataItemIndex+1 %> 
       </ItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="tid" SortExpression="tid" Visible="false"> 
       <ItemTemplate> 
        <asp:Label ID="lblID" runat="server" Text='<%# Bind("tid") %>'></asp:Label> 
       </ItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Title" SortExpression="title"> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtTitle1" runat="server" Text='<%# Bind("title") %>'></asp:TextBox> 
       </EditItemTemplate> 
       <ItemTemplate> 
        <asp:Label ID="lblTitle" runat="server" Text='<%# Bind("title") %>'></asp:Label> 
       </ItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Category" SortExpression="category"> 
       <ItemTemplate> 
        <asp:Label ID="lblCategory" runat="server" Text='<%# Bind("category") %>'></asp:Label></ItemTemplate> 
       <EditItemTemplate> 
        <asp:RadioButtonList ID="rbtnlist" runat="server"><asp:ListItem Text="Soft Skills"></asp:ListItem><asp:ListItem Text="Technical Skills"></asp:ListItem></asp:RadioButtonList> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Announced at" SortExpression="dt">      
       <ItemTemplate> 
        <asp:Label ID="lblDt" runat="server" Text='<%# Bind("dt", "{0:dd/MMM/yyyy HH:mm tt}") %>'></asp:Label> 
       </ItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Year" SortExpression="year"> 
       <EditItemTemplate> 
        <asp:DropDownList ID="ddlyr" runat="server"></asp:DropDownList> 
       </EditItemTemplate> 
       <ItemTemplate> 
        <asp:Label ID="lblyr" runat="server" Text='<%# Bind("year") %>'></asp:Label> 
       </ItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="User Id" SortExpression="userid">      
       <ItemTemplate> 
        <asp:Label ID="lblUid" runat="server" Text='<%# Bind("userid") %>'></asp:Label> 
       </ItemTemplate> 
      </asp:TemplateField>       
      <asp:TemplateField ShowHeader="False"> 
       <ItemTemplate> 
        <asp:LinkButton ID="btndel" runat="server" CausesValidation="False" CommandName="Delete" Text="Delete" OnClientClick="return isConfirm()" Visible="false"></asp:LinkButton>            

         <%--<asp:LinkButton ID="btnmail" runat="server" CausesValidation="False" OnClientClick="return isConfirm()" Text="Send Mail" Visible="false"></asp:LinkButton>--%> 

         </ItemTemplate>      
      </asp:TemplateField>   
      <asp:TemplateField ShowHeader="False"> 
       <EditItemTemplate> 
        <asp:LinkButton ID="btnupdte" runat="server" CausesValidation="True" CommandName="Update" Text="Update"></asp:LinkButton> 
        &nbsp;<asp:LinkButton ID="btncncl" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton> 
       </EditItemTemplate> 
       <ItemTemplate> 
        <asp:LinkButton ID="btnedit" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit" Visible="false"></asp:LinkButton> 
       </ItemTemplate> 
      </asp:TemplateField>    
      <asp:TemplateField ShowHeader="false"> 
        <ItemTemplate> 
         <asp:LinkButton ID="btnmail" runat="server" CausesValidation="False" OnClientClick="return isConfirm()" Text="Send Mail" Visible="false"></asp:LinkButton> 
        </ItemTemplate> 
       </asp:TemplateField>     
      </Columns> 
     <FooterStyle BackColor="#99CCCC" ForeColor="#003399" /> 
     <HeaderStyle BackColor="#003399" Font-Bold="True" ForeColor="#CCCCFF" /> 
     <PagerStyle ForeColor="#003399" HorizontalAlign="Left" BackColor="#99CCCC" /> 
     <RowStyle BackColor="White" ForeColor="#003399" /> 
     <SelectedRowStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" /> 
     <SortedAscendingCellStyle BackColor="#EDF6F6" /> 
     <SortedAscendingHeaderStyle BackColor="#0D4AC4" /> 
     <SortedDescendingCellStyle BackColor="#D6DFDF" /> 
     <SortedDescendingHeaderStyle BackColor="#002876" /> 
    </asp:GridView> 

C＃

protected void gv1_RowDataBound(object sender, GridViewRowEventArgs e) 
    { 
     if (e.Row.RowType == DataControlRowType.DataRow) 
     { 

      Label lbly = (Label)e.Row.FindControl("lblyr"); 
      if (lbly.Text == DateTime.Now.Year.ToString() || lbly.Text == ((DateTime.Now.Year)-1).ToString()) 
      { 

       LinkButton btedt = (LinkButton)e.Row.FindControl("btnedit"); 
       LinkButton btdel = (LinkButton)e.Row.FindControl("btndel"); 
       LinkButton btsm = (LinkButton)e.Row.FindControl("btnmail"); 
       btdel.Visible = true; 
       btedt.Visible = true; 
       btsm.Visible = true; 

      } 
      if ((e.Row.RowState & DataControlRowState.Edit) > 0) { 
       RadioButtonList rbtnlist = (RadioButtonList)e.Row.FindControl("rbtnlist");     
       DropDownList ddlist = (DropDownList)e.Row.FindControl("ddlyr"); 
       for (int i = (DateTime.Now.Year); i >= ((DateTime.Now.Year)-1) ; i--) 
       { 
        ddlist.Items.Add(new ListItem(i.ToString(), i.ToString())); 
       } 

       ddlist.DataBind(); 
       rbtnlist.DataBind(); 
      } 
     } 

    } 

Answer 1

我假设你正在与一个DataTable结合网格柱面名称“年”。尝试下面的代码，其中dt代表您的数据表：

protected void gv1_RowDataBound(object sender, GridViewRowEventArgs e) 
    { 
     if (e.Row.RowType == DataControlRowType.DataRow) 
     { 
      int rowno = e.Row.DataItemIndex; 
      //Suppose dt is DataTable to which you are binding your grid 
      //and year is the column name within this datatable 
      string year = Convert.ToString(dt.Rows[e.Row.DataItemIndex]["year"]); 
      if (year == DateTime.Now.Year.ToString() || year == ((DateTime.Now.Year) - 1).ToString()) 
      { 

       LinkButton btedt = (LinkButton)e.Row.FindControl("btnedit"); 
       LinkButton btdel = (LinkButton)e.Row.FindControl("btndel"); 
       LinkButton btsm = (LinkButton)e.Row.FindControl("btnmail"); 
       btdel.Visible = true; 
       btedt.Visible = true; 
       btsm.Visible = true; 

      } 
      if ((e.Row.RowState & DataControlRowState.Edit) > 0) 
      { 
       RadioButtonList rbtnlist = (RadioButtonList)e.Row.FindControl("rbtnlist"); 
       DropDownList ddlist = (DropDownList)e.Row.FindControl("ddlyr"); 
       for (int i = (DateTime.Now.Year); i >= ((DateTime.Now.Year) - 1); i--) 
       { 
        ddlist.Items.Add(new ListItem(i.ToString(), i.ToString())); 
       } 

       ddlist.DataBind(); 
       rbtnlist.DataBind(); 
      } 
     }