在 gridView 中显示数据时出现 'Object reference not set to an instance of an object.' 错误

Question

我想在用户单击 'Save' 按钮时将详细信息（作为输入从用户处获取）添加到网格视图中。但是当我点击 'save' 按钮时出现 'Object reference not set to an instance of an object' 错误。

这是后面的代码，

 protected void btnSave_Click(object sender, EventArgs e)
    {
        string rootCaseID = txtRootCaseID.Text;
        string root = txtRoot.Text;
        string description = txtDes.Text;

        DataTable rottCasetTbl = null;
        DataRow dr = null; ;
        dr["id"] = txtRootCaseID.Text;
        dr["root"] = txtRoot.Text;
        dr["description"] = txtDes.Text;
        rottCasetTbl.Rows.Add(dr);
        grdrootCase.DataSource = rottCasetTbl;
        grdrootCase.DataBind();

    }

前端代码，

 <tr>
    <td align="center">
          <asp:GridView ID="grdrootCase" runat="server" ShowHeaderWhenEmpty="true" 
                            EmptyDataText="No Records Found" AutoGenerateColumns="False" 
                            CellPadding="4" ForeColor="#333333" 
                            GridLines="None" Font-Size="Small" 
                            Width="95%">
                            <AlternatingRowStyle BackColor="White" />

                            <Columns>

                                <asp:BoundField HeaderText="Root Case ID" DataField="id" />
                                <asp:BoundField HeaderText="Root" DataField="root" />
                                <asp:BoundField HeaderText="Description" DataField="description" />
                            </Columns>

                            <EditRowStyle BackColor="#2461BF" />
                            <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                            <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                            <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                            <RowStyle BackColor="#EFF3FB" />
                            <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
                            <SortedAscendingCellStyle BackColor="#F5F7FB" />
                            <SortedAscendingHeaderStyle BackColor="#6D95E1" />
                            <SortedDescendingCellStyle BackColor="#E9EBEF" />
                            <SortedDescendingHeaderStyle BackColor="#4870BE" />
                        </asp:GridView>

        </td>
    </tr>

谁能帮我解决这个问题。

Answer 1

您的 DataTable 设置为 null，您的 DataRow 也是如此

改变

DataTable rottCasetTbl = null;
DataRow dr = null;

至

DataTable rottCasetTbl = new  DataTable();
//add the columns
rottCasetTbl.Columns.Add("id", typeof(String));
rottCasetTbl.Columns.Add("root", typeof(String));
rottCasetTbl.Columns.Add("description", typeof(String));
DataRow dr = rottCasetTbl.NewRow();

在 gridView 中显示数据时出现 'Object reference not set to an instance of an object.' 错误

Getting error of 'Object reference not set to an instance of an object.' when displaying data in a gridView

c#

asp.net

gridview