Question

我正在创建一个包含两个网格视图的页面，其中一个事件负责另一个网格视图中的内容。（就像你有一个任务而你的任务有一些步骤，所以当你从一个任务列表中点击一个任务时，你可以看到一个与该任务相关的步骤表）但我正如上面那样面对例外。有人可以帮我解决一下吗？

的Index.aspx

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <!-- Bootstrap core CSS-->
    <link href="../Content/bootstrap.min.css" rel="stylesheet" />
    <!-- Custom styles for this template -->
    <link href="../Styles/dashboard.css" rel="stylesheet" />
    <style>
        td, th
        {
            border-color: rgb(222, 226, 230);
        }
    </style>
</head>
<body>
<form id="form1" runat="server">
    <div class='table - responsive'>
        <asp:GridView ID="tasklistsGridView" runat="server" AutoGenerateColumns="False" ShowFooter="True" DataKeyNames="Id" AllowPaging="True" CellPadding="3" OnPageIndexChanging="tasklistsGridView_PageIndexChanging" OnRowDeleting="tasklistsGridView_RowDeleting" OnRowEditing="tasklistsGridView_RowEditing" OnRowUpdating="tasklistsGridView_RowUpdating" OnRowCancelingEdit="tasklistsGridView_RowCancelingEdit" PageSize="4" BackColor="#ffffff" BorderColor="#ffffff" BorderStyle="Solid" BorderWidth="0px"  CellSpacing="2" OnRowCommand="tasklistsGridView_RowCommand" class='table table - striped table - sm' OnSelectedIndexChanged="tasklistsGridView_SelectedIndexChanged"> 
            <Columns>
                <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False"  ReadOnly="True" SortExpression="Id" />

                <asp:TemplateField HeaderText="Name" SortExpression="Name">
                    <EditItemTemplate>
                        <asp:TextBox ID="txtName" Width="100px" runat="server" Text='<%# Bind("Name") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtName" runat="server"  Width="100px"></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Bind("Name") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Description" SortExpression="Description">
                    <EditItemTemplate>
                        <asp:TextBox ID="txtDescription"  Width="100px" runat="server" Text='<%# Bind("Description") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtDescription" Width="100px" runat="server" ></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label2" runat="server" Text='<%# Bind("Description") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Prerequisites" SortExpression="Prerequisites">
                    <EditItemTemplate>
                        <asp:TextBox ID="txtPrerequisites"  Width="100px" runat="server" Text='<%# Bind("Prerequisites") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtPrerequisites"  Width="100px" runat="server" ></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label3" runat="server" Text='<%# Bind("Prerequisites") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Workgroup" SortExpression="Workgroup">
                    <EditItemTemplate>
                        <asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="name" DataValueField="Id">
                        </asp:DropDownList>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="name" DataValueField="Id">
                        </asp:DropDownList>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label5" runat="server" Text='<%# Bind("Workgroup") %>'></asp:Label>
                        &nbsp;
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Tag" SortExpression="Tag">
                    <EditItemTemplate>
                        <asp:TextBox ID="txtTag" Width="100px" runat="server" Text='<%# Bind("Tag") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtTag" Width="100px" runat="server" ></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label4" runat="server" Text='<%# Bind("Tag") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Edit" ShowHeader="False">
                    <EditItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True" CommandName="Update" Text="Update"></asp:LinkButton>
                        <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="AddNew" Text="Add New"></asp:LinkButton>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:CommandField HeaderText="Delete" ShowDeleteButton="True"  ShowHeader="True" />

                <asp:CommandField HeaderText="Objectives" ShowSelectButton="True"  ShowHeader="True" />

            </Columns>

            <EmptyDataTemplate>
                <h3>No available tasklists! Create a new one?</h3>
                <form role="form">
                    <div class="form-group">
                        <label class="control-label" for="name">Name</label>
                        <asp:TextBox ID="newTasklistName" type="text" class="form-control" placeholder="Enter Tasklist Name" runat="server"></asp:TextBox>
                    </div>
                    <div class="form-group">
                        <label class="control-label" for="description">Description</label>
                        <asp:TextBox ID="newTasklistDescription" type="text" class="form-control" placeholder="Describe your Tasklist" runat="server"></asp:TextBox>
                    </div>
                    <div class="form-group">
                        <label class="control-label" for="prerequisites">Prerequisites</label>
                        <asp:TextBox ID="newTasklistPrerequisites" type="text" class="form-control" placeholder="Enter Prerequisites for your Tasklist" runat="server"></asp:TextBox>
                    </div>
                    <div class="form-group">
                        &nbsp;<div class="btn-group dropdown">
                            <asp:Button ID="workgroupDropdownLabel" type="button" class="btn btn-light  dropdown-toggle" runat="server" Text="Workgroups" style="padding-left: 0.4em;" />
                            <asp:DropDownList ID="workgroupDropdown" type="button" class="btn btn-light" runat="server" style="position:relative; left:-0.3em; top: 0.1em; padding-left: 0.1em;" DataSourceID="SqlDataSource1" DataTextField="name" DataValueField="Id"></asp:DropDownList>
                        </div>
                    </div>
                    <div class="form-group">
                        <label class="control-label" for="tag">Tag</label>
                        <asp:TextBox ID="newTasklistTag" type="text" class="form-control" placeholder="Tag your Tasklist" runat="server"></asp:TextBox>
                    </div>
                    <asp:Button ID="newTasklistSubmitButton" class="btn btn-default" runat="server" Text="Submit" />
                </form>
            </EmptyDataTemplate>

            <%--<RowStyle BackColor="#FFF7E7" ForeColor="#8C4510" />

            <FooterStyle BackColor="#F7DFB5" ForeColor="#8C4510" />

            <PagerStyle ForeColor="#8C4510" HorizontalAlign="Center" />--%>

            <SelectedRowStyle BackColor="#505050" Font-Bold="True" ForeColor="White" />

            <%--<HeaderStyle BackColor="white" Font-Bold="True" ForeColor="White" />--%>
            </asp:GridView>
    </div>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:SOP3ConnectionString %>" SelectCommand="SELECT [name], [Id] FROM [workgroup]" ProviderName="System.Data.SqlClient"></asp:SqlDataSource>
















    <div class='table - responsive'>
        <asp:GridView ID="objectivesGridView" runat="server" AutoGenerateColumns="False" ShowFooter="True" DataKeyNames="Id" AllowPaging="True" CellPadding="3" OnPageIndexChanging="objectivesGridView_PageIndexChanging" OnRowDeleting="objectivesGridView_RowDeleting" OnRowEditing="objectivesGridView_RowEditing" OnRowUpdating="objectivesGridView_RowUpdating" OnRowCancelingEdit="objectivesGridView_RowCancelingEdit" PageSize="5" BackColor="#ffffff" BorderColor="#ffffff" BorderStyle="None" BorderWidth="0px" CellSpacing="2" OnRowCommand="objectivesGridView_RowCommand" class='table table - striped table - sm'> 
            <Columns>
                <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False"  ReadOnly="True" SortExpression="Id" />

                <asp:TemplateField HeaderText="Objective" SortExpression="Objective">
                    <EditItemTemplate>
                        <asp:TextBox ID="txtObjective" Width="100px" runat="server" Text='<%# Bind("Objective") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtObjective" runat="server"  Width="100px"></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Bind("Objective") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Tasklist" SortExpression="Tasklist">
                    <EditItemTemplate>
                        <asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="SqlDataSource2" DataTextField="name" DataValueField="Id">
                        </asp:DropDownList>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="SqlDataSource2" DataTextField="name" DataValueField="Id">
                        </asp:DropDownList>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label5" runat="server" Text='<%# Bind("Tasklist") %>'></asp:Label>
                        &nbsp;
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Edit" ShowHeader="False">
                    <EditItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True" CommandName="Update" Text="Update"></asp:LinkButton>
                        <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="AddNew" Text="Add New"></asp:LinkButton>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:CommandField HeaderText="Delete" ShowDeleteButton="True"  ShowHeader="True" />


            </Columns>

            <EmptyDataTemplate>
                <h3>No available objectives for the selected tasklist! Create a new one?</h3>
                <form role="form">
                    <div class="form-group">
                        <label class="control-label" for="name">Name</label>
                        <asp:TextBox ID="newObjective" type="text" class="form-control" placeholder="Enter Objective" runat="server"></asp:TextBox>
                    </div>
                    <div class="form-group">
                        &nbsp;<div class="btn-group dropdown">
                            <asp:Button ID="tasklistDropdownLabel" type="button" class="btn btn-light  dropdown-toggle" runat="server" Text="Tasklists" style="padding-left: 0.4em;" />
                            <asp:DropDownList ID="tasklistDropdown" type="button" class="btn btn-light" runat="server" style="position:relative; left:-0.3em; top: 0.1em; padding-left: 0.1em;" DataSourceID="SqlDataSource2" DataTextField="name" DataValueField="Id"></asp:DropDownList>
                        </div>
                    </div>
                    <asp:Button ID="newObjectiveSubmitButton" class="btn btn-default" runat="server" Text="Submit" />
                </form>
            </EmptyDataTemplate>

            <%--<RowStyle BackColor="#FFF7E7" ForeColor="#8C4510" />

            <FooterStyle BackColor="#F7DFB5" ForeColor="#8C4510" />

            <PagerStyle ForeColor="#8C4510" HorizontalAlign="Center" />--%>

            <SelectedRowStyle BackColor="#505050" Font-Bold="True" ForeColor="White" />

            <%--<HeaderStyle BackColor="white" Font-Bold="True" ForeColor="White" />--%>
            </asp:GridView>
    </div>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString2 %>" SelectCommand="SELECT [name], [Id] FROM [tasklist]" ProviderName="System.Data.SqlClient"></asp:SqlDataSource>



    <!-- Bootstrap core JavaScript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
<script src="../Scripts/jquery-3.3.1.slim.min.js"></script>
<script>window.jQuery || document.write('<script src="../Scripts/jquery-3.3.1-slim.min.js"><\/script>')</script>
<script src="../Scripts/umd/popper.min.js"></script>
<script src="../Scripts/bootstrap.min.js"></script>

<!-- Icons -->
<script src="../Scripts/feather.min.js"></script>
<script>
  feather.replace()
</script>

<!-- Custom Scripts -->
<script>
    var tables = document.getElementsByTagName('table');

    for (var i = 0; i < tables.length; i++)
    {
        document.getElementsByTagName('table')[i].className += " table-hover";
        document.getElementsByTagName('table')[i].className += " thead-dark";
        document.getElementsByTagName('table')[i].className += " table-responsive-sm";
    }
</script>
</form>

index.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public partial class index : System.Web.UI.Page
{
    SqlConnection connection = new SqlConnection(ConfigurationManager.AppSettings["ConnectionString"].ToString());
    SqlDataAdapter adapter = new SqlDataAdapter();
    SqlCommand command = new SqlCommand();
    DataTable table = new DataTable();

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        showTasklists();
    }
}

private void showTasklists()
{
    try
    {
        command.Connection = connection;
        command.CommandText = "select * from tasklist";
        adapter = new SqlDataAdapter(command);
        adapter.Fill(table);
        tasklistsGridView.DataSource = table;
        tasklistsGridView.DataBind();
    }
    catch (Exception x)
    {
        Response.Write("Exception: " + x.Message);
    }
}

protected void tasklistsGridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
    tasklistsGridView.PageIndex = e.NewPageIndex;
    showTasklists();
}

protected void tasklistsGridView_RowDeleting(object sender, GridViewDeleteEventArgs e)

{
    try
    {
        command.Connection = connection;
        command.CommandText = "delete from tasklist where Id='" + tasklistsGridView.DataKeys[e.RowIndex].Values[0].ToString() + "'";
        connection.Open();
        command.ExecuteNonQuery();
        connection.Close();
        showTasklists();
    }
    catch (Exception x)
    {
        Response.Write("Exception: " + x.Message);
    }
}

protected void tasklistsGridView_RowEditing(object sender, GridViewEditEventArgs e)
{
    tasklistsGridView.EditIndex = e.NewEditIndex;
    showTasklists();
}

protected void tasklistsGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    try
    {
        TextBox txtName = (TextBox)tasklistsGridView.Rows[e.RowIndex].FindControl("txtName");
        TextBox txtDescription = (TextBox)tasklistsGridView.Rows[e.RowIndex].FindControl("txtDescription");
        TextBox txtPrerequisites = (TextBox)tasklistsGridView.Rows[e.RowIndex].FindControl("txtPrerequisites");
        DropDownList ddlWorkgroup = (DropDownList)tasklistsGridView.FooterRow.FindControl("DropDownList1");
        TextBox txtTag = (TextBox)tasklistsGridView.Rows[e.RowIndex].FindControl("txtTag");
        command.Connection = connection;
        command.CommandText = "update tasklist set name ='" + txtName.Text + "',description ='" + txtDescription.Text + "',prerequisites ='" + txtPrerequisites.Text + "',workgroup ='" + ddlWorkgroup.SelectedItem.ToString() + "',tag ='" + txtTag.Text + "'   WHERE Id='" + tasklistsGridView.DataKeys[e.RowIndex].Values[0].ToString() + "'";
        connection.Open();
        command.ExecuteNonQuery();
        tasklistsGridView.EditIndex = -1;
        showTasklists();
        connection.Close();
    }
    catch (Exception x)
    {
        Response.Write("Exception: " + x.Message);
    }
}

protected void tasklistsGridView_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
    tasklistsGridView.EditIndex = -1;
    showTasklists();
}

protected void tasklistsGridView_RowCommand(object sender, GridViewCommandEventArgs e)
{
    try
    {
        if (e.CommandName.Equals("AddNew"))
        {
            TextBox txtName = (TextBox)tasklistsGridView.FooterRow.FindControl("txtName");
            TextBox txtDescription = (TextBox)tasklistsGridView.FooterRow.FindControl("txtDescription");
            TextBox txtPrerequisites = (TextBox)tasklistsGridView.FooterRow.FindControl("txtPrerequisites");
            DropDownList ddlWorkgroup = (DropDownList)tasklistsGridView.FooterRow.FindControl("DropDownList1");
            TextBox txtTag = (TextBox)tasklistsGridView.FooterRow.FindControl("txtTag");
            command.Connection = connection;
            command.CommandText = "insert into tasklist(name, description,prerequisites,workgroup,tag) Values('" + txtName.Text + "', '" + txtDescription.Text + "', '" + txtPrerequisites.Text + "', '" + ddlWorkgroup.SelectedItem.ToString() + "', '" + txtTag.Text + "')";
            connection.Open();
            command.ExecuteNonQuery();
            showTasklists();
            connection.Close();
        }
    }
    catch (Exception x)
    {
        Response.Write("Exception: " + x.Message);
    }
}

protected void tasklistsGridView_SelectedIndexChanged(object sender, EventArgs e)
{
    ViewState["tasklistid"] = tasklistsGridView.SelectedRow.Cells[0].Text;
    try
    {
        //2. Open Connection
        connection.Open();

        //3. Create and Execute Command
        string query = "select Id, objective from objectives where tasklistId='" + Convert.ToInt32(ViewState["tasklistid"]) + "';";
        SqlCommand command = new SqlCommand();
        command.Connection = connection;
        command.CommandText = query;
        SqlDataReader reader = command.ExecuteReader();
        DataTable Table = new DataTable();
        Table.Load(reader);
        objectivesGridView.DataSource = Table;
        objectivesGridView.DataBind();

        //4. Close connection
        connection.Close();
    }
    catch (Exception x)
    {
        Response.Write("exception: " + x.Message);
    }
}













private void showObjectives()
{
    try
    {
        command.Connection = connection;
        command.CommandText = "select * from objectives";
        adapter = new SqlDataAdapter(command);
        adapter.Fill(table);
        objectivesGridView.DataSource = table;
        objectivesGridView.DataBind();
    }
    catch (Exception x)
    {
        Response.Write("showObjectivesException: " + x.Message);
    }
}

protected void objectivesGridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
    objectivesGridView.PageIndex = e.NewPageIndex;
    showObjectives();
}

protected void objectivesGridView_RowDeleting(object sender, GridViewDeleteEventArgs e)

{
    try
    {
        command.Connection = connection;
        command.CommandText = "delete from objectives where Id='" + objectivesGridView.DataKeys[e.RowIndex].Values[0].ToString() + "'";
        connection.Open();
        command.ExecuteNonQuery();
        connection.Close();
        showObjectives();
    }
    catch (Exception x)
    {
        Response.Write("objectivesGridView_RowDeletingException: " + x.Message);
    }
}

protected void objectivesGridView_RowEditing(object sender, GridViewEditEventArgs e)
{
    objectivesGridView.EditIndex = e.NewEditIndex;
    showObjectives();
}

protected void objectivesGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    try
    {
        TextBox txtObjective = (TextBox)objectivesGridView.Rows[e.RowIndex].FindControl("txtObjective");
        DropDownList ddlObjectives = (DropDownList)objectivesGridView.FooterRow.FindControl("DropDownList2");
        command.Connection = connection;
        command.CommandText = "update objectives set objective ='" + txtObjective.Text + "',tasklistId ='" + ddlObjectives.SelectedItem + "'   WHERE Id='" + objectivesGridView.DataKeys[e.RowIndex].Values[0].ToString() + "'";
        connection.Open();
        command.ExecuteNonQuery();
        objectivesGridView.EditIndex = -1;
        showObjectives();
        connection.Close();
    }
    catch (Exception x)
    {
        Response.Write("objectivesGridView_RowUpdatingException: " + x.Message);
    }
}

protected void objectivesGridView_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
    objectivesGridView.EditIndex = -1;
    showObjectives();
}

protected void objectivesGridView_RowCommand(object sender, GridViewCommandEventArgs e)
{
    try
    {
        if (e.CommandName.Equals("AddNew"))
        {
            TextBox txtObjective = (TextBox)objectivesGridView.FooterRow.FindControl("txtObjective");
            DropDownList ddlObjective = (DropDownList)objectivesGridView.FooterRow.FindControl("DropDownList2");
            command.Connection = connection;
            command.CommandText = "insert into objectives(objective,tasklistId) Values('" + txtObjective.Text + "', '" + ddlObjective.SelectedItem + "')";
            connection.Open();
            command.ExecuteNonQuery();
            showObjectives();
            connection.Close();
        }
    }
    catch (Exception x)
    {
        Response.Write("objectivesGridView_RowCommandException: " + x.Message);
    }
}
}

Here's the output snap (you might want to look at that red arrow on the top)

Answer 1

检查所有查询是否都返回名为Tasklist

的字段

<asp:Label ID="Label5" runat="server" Text='<%# Bind("Tasklist")%>'></asp:Label>

DataBinding：＆＃39; System.Data.DataRowView＆＃39;不包含名称为＆＃39;任务列表＆＃39;的属性。

1 个答案: