c# - "value cannot be null parameter name: key"

Question

我在调试我正在处理的网站时遇到“蓝屏死机”。错误信息是“value cannot be null. Parameter name: key.”我正在尝试将 formview 绑定(bind)到 gridview 的选定索引。当我在我的 selectedindexchanged 方法中设置断点时，一切似乎都正确绑定(bind)，我可以查看我的 formview 的值，但是当我继续运行它时，我收到上述错误消息。我尝试将 datakeynames 属性添加到 formview 并得到相同的错误消息。我在这里和谷歌搜索并看到了一些结果，但似乎没有一个能解决或与我的问题相关。

部分代码如下:

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
    lblMessage.Text = "";
    cbCalled.Visible = true;
    cbError.Visible = true;
    cbVerbal.Visible = true;
    btnSubmit.Visible = true;
    FormView1.Visible = true;
    FormView1.DataBind();
    FormView fv1 = FormView1;
    Label PathCountLabel = (Label)fv1.FindControl("pathcountLabel");
    TextBox PathResult = (TextBox)fv1.FindControl("PathResultLabel");
    if ((PathCountLabel.Text != "1 of 1 biopsies") && (PathCountLabel.Text != "Only 1 Pathology Ordered"))
    {
        PathResult.BackColor = ColorTranslator.FromHtml("#FFFFAA");
    }
}

 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
        Visible="False" DataKeyNames="PatientID" DataSourceID="SqlDataSource1" 
        onselectedindexchanged="GridView1_SelectedIndexChanged" AllowSorting="True" onsorting="GridView1_Sorting">
    <Columns>
        <asp:CommandField ShowSelectButton="True" />
        <asp:BoundField DataField="PatientID" HeaderText="Patient Id" SortExpression="PatientID" />
        <asp:BoundField DataField="LastName" HeaderText="Last Name" 
            SortExpression="LastName" />
        <asp:BoundField DataField="FirstName" HeaderText="First Name" 
            SortExpression="FirstName" />
        <asp:BoundField DataField="PathCount" HeaderText="Path Count" 
            SortExpression="PathCount" />
        <asp:BoundField DataField="DateOfService" DataFormatString="{0:d}" 
            HeaderText="Date of Service" SortExpression="DateOfService" />
    </Columns>
</asp:GridView>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
        ConnectionString="<%$ ConnectionStrings:PathologyConnectionString %>" 
        SelectCommand="SELECT * FROM [PatientDB]">
    </asp:SqlDataSource>
<br />
</div>
<div id="rightCol">
<asp:FormView ID="FormView1" runat="server" DataSourceID="SqlDataSource2" 
    Width="708px">
    <EditItemTemplate>
        LastName:
        <asp:TextBox ID="LastNameTextBox" runat="server" 
            Text='<%# Bind("LastName") %>' />
        <br />
        FirstName:
        <asp:TextBox ID="FirstNameTextBox" runat="server" 
            Text='<%# Bind("FirstName") %>' />
        <br />
        DOB:
        <asp:TextBox ID="DOBTextBox" runat="server" 
            Text='<%# Bind("DOB") %>' />
        <br />
        PhoneNumber:
        <asp:TextBox ID="PhoneNumberTextBox" runat="server" 
            Text='<%# Bind("PhoneNumber") %>' />
        <br />
        ChartNumber:
        <asp:TextBox ID="ChartNumberTextBox" runat="server" 
            Text='<%# Bind("ChartNumber") %>' />
        <br />
        AccountNumber:
        <asp:TextBox ID="AccountNumberTextBox" runat="server" 
            Text='<%# Bind("AccountNumber") %>' />
        <br />
        PathResult:
        <asp:TextBox ID="PathResultTextBox" runat="server" 
            Text='<%# Bind("PathResult") %>' />
        <br />
        PreviousVisitNote:
        <asp:TextBox ID="PreviousVisitNoteTextBox" runat="server" 
            Text='<%# Bind("PreviousVisitNote") %>' />
        <br />
        PathSlipNote:
        <asp:TextBox ID="PathSlipNoteTextBox" runat="server" 
            Text='<%# Bind("PathSlipNote") %>' />
        <br />
        PathSlipCheckboxes:
        <asp:TextBox ID="PathSlipCheckboxesTextBox" runat="server" 
            Text='<%# Bind("PathSlipCheckboxes") %>' />
        <br />
        <asp:LinkButton ID="UpdateButton" runat="server" CausesValidation="True" 
            CommandName="Update" Text="Update" />
        &nbsp;<asp:LinkButton ID="UpdateCancelButton" runat="server" 
            CausesValidation="False" CommandName="Cancel" Text="Cancel" />
    </EditItemTemplate>
    <InsertItemTemplate>
        LastName:
        <asp:TextBox ID="LastNameTextBox" runat="server" 
            Text='<%# Bind("LastName") %>' />
        <br />
        FirstName:
        <asp:TextBox ID="FirstNameTextBox" runat="server" 
            Text='<%# Bind("FirstName") %>' />
        <br />
        DOB:
        <asp:TextBox ID="DOBTextBox" runat="server" 
            Text='<%# Bind("DOB") %>' />
        <br />
        PhoneNumber:
        <asp:TextBox ID="PhoneNumberTextBox" runat="server" 
            Text='<%# Bind("PhoneNumber") %>' />
        <br />
        ChartNumber:
        <asp:TextBox ID="ChartNumberTextBox" runat="server" 
            Text='<%# Bind("ChartNumber") %>' />
        <br />
        AccountNumber:
        <asp:TextBox ID="AccountNumberTextBox" runat="server" 
            Text='<%# Bind("AccountNumber") %>' />
        <br />
        PathResult:
        <asp:TextBox ID="PathResultTextBox" runat="server" 
            Text='<%# Bind("PathResult") %>' />
        <br />
        PreviousVisitNote:
        <asp:TextBox ID="PreviousVisitNoteTextBox" runat="server" 
            Text='<%# Bind("PreviousVisitNote") %>' />
        <br />
        PathSlipNote:
        <asp:TextBox ID="PathSlipNoteTextBox" runat="server" 
            Text='<%# Bind("PathSlipNote") %>' />
        <br />
        PathSlipCheckboxes:
        <asp:TextBox ID="PathSlipCheckboxesTextBox" runat="server" 
            Text='<%# Bind("PathSlipCheckboxes") %>' />
        <br />
        <asp:LinkButton ID="InsertButton" runat="server" CausesValidation="True" 
            CommandName="Insert" Text="Insert" />
        &nbsp;<asp:LinkButton ID="InsertCancelButton" runat="server" 
            CausesValidation="False" CommandName="Cancel" Text="Cancel" />
    </InsertItemTemplate>
    <ItemTemplate>
        Last Name:
        <asp:Label ID="LastNameLabel" runat="server" Text='<%# Bind("LastName") %>' />
        &nbsp;&nbsp;&nbsp;&nbsp; First Name:
        <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Bind("FirstName") %>' />
        &nbsp;&nbsp;&nbsp;&nbsp; DOB:
        <asp:Label ID="DOBLabel" runat="server" Text='<%# Bind("DOB") %>' />
        &nbsp;&nbsp;
        <br />
        <br />
        Phone Number:
        <asp:Label ID="PhoneNumberLabel" runat="server" 
            Text='<%# Bind("PhoneNumber") %>' />
        &nbsp;&nbsp;&nbsp;&nbsp; Chart Number:
        <asp:Label ID="ChartNumberLabel" runat="server" 
            Text='<%# Bind("ChartNumber") %>' />
        &nbsp;&nbsp;&nbsp; Account Number:
        <asp:Label ID="AccountNumberLabel" runat="server" 
            Text='<%# Bind("AccountNumber") %>' />
        <br />
        <br />
        Biopsy Location:
        <asp:Label ID="BiopsyLocationLabel" runat="server" Text='<%# Bind("BiopsyArea") %>'></asp:Label>
        <br />
        <br />
        Path Result:
        <br />
                    <asp:TextBox ID="PathResultLabel" runat="server" 
            Text='<%# Bind("PathResult") %>' ReadOnly="True" TextMode="MultiLine" Width="600" Height="250" />

        <br />
        <br />
        Previous Visit Note:<br />
        <asp:TextBox ID="PreviousVisitNoteLabel" runat="server" 
            Text='<%# Bind("PreviousVisitNote") %>' ReadOnly="True" TextMode="MultiLine" Width="600" Height="250" />
        <br />
        <br />
        Pathology Lab Note:<br />
        <asp:TextBox ID="txtPathNote" runat="server" 
            Text='<%# Bind("PathNote") %>' ReadOnly="True" TextMode="MultiLine" Width="600" Height="150" />
        <br />
        <br />
        Note to DA/DT:<br />
        <asp:TextBox ID="txtDADTNote" runat="server" 
            Text='<%# Bind("DADTNote") %>' ReadOnly="True" TextMode="MultiLine" Width="600" Height="150" />
        <br />
        <br />
        Path Slip Note:<br />
        <asp:Label ID="PathSlipNoteLabel" runat="server" 
            Text='<%# Bind("PathSlipNote") %>' />
        <br />
        <br />
        Path Slip Checkboxes:
        <br />
        <asp:Label ID="PathSlipCheckboxesLabel" runat="server" 
            Text='<%# Bind("PathSlipCheckboxes") %>' />
        <br />
        <br />
        Patient Message:<br />
        <ASPNetSpell:SpellTextBox ID="txtPatientMessage" runat="server" TextMode="MultiLine" 
    DictionaryLanguage="English (International), English (Medical)" Height="88px" 
    Width="597px" Text='<%# Bind("PatientMessage") %>' onKeyPress="return macro(event);"></ASPNetSpell:SpellTextBox>
    <br />
    <asp:Label ID="pathcountLabel" runat="server" Text = '<%# Bind("PathCount") %>' Visible="false"></asp:Label>
    </ItemTemplate>
</asp:FormView>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" 
    ConnectionString="<%$ ConnectionStrings:PathologyConnectionString %>" 

    SelectCommand="SELECT [LastName], [FirstName], [DOB], [PhoneNumber], [ChartNumber], [AccountNumber], [PathResult], [PreviousVisitNote], [PathSlipNote], [PathSlipCheckboxes], [PathNote], [DADTNote], [BiopsyArea], [PatientMessage], [PathCount] FROM [PatientDB] WHERE ([PatientID] = @PatientID)">
    <SelectParameters>
        <asp:ControlParameter ControlID="GridView1" Name="PatientID" 
            PropertyName="SelectedValue" Type="Int32" />
    </SelectParameters>
</asp:SqlDataSource>

我添加了来自 YSOD 的堆栈跟踪

Server Error in '/' Application.
--------------------------------------------------------------------------------


Value cannot be null.
Parameter name: key 
  Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

 Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: key

Source Error: 


 An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  

Stack Trace: 



[ArgumentNullException: Value cannot be null.
Parameter name: key]
   System.Collections.Generic.Dictionary`2.FindEntry(TKey key) +10627293
   System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value) +12
   Microsoft.VisualStudio.Web.PageInspector.Runtime.WebForms.SelectionMappingRenderTraceListener.GetLiteralTraceData(LiteralControl literal, TraceData& data) +97
   Microsoft.VisualStudio.Web.PageInspector.Runtime.WebForms.SelectionMappingRenderTraceListener.GetTraceData(Object renderedObject) +421
   Microsoft.VisualStudio.Web.PageInspector.Runtime.WebForms.SelectionMappingRenderTraceListener.EndRendering(TextWriter writer, Object renderedObject) +79
   System.Web.UI.RenderTraceListenerList.EndRendering(TextWriter writer, Object renderedObject) +58
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +142
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   ASPNetSpell.SpellTextBox.Render(HtmlTextWriter writer) +6035
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   System.Web.UI.WebControls.TableCell.RenderContents(HtmlTextWriter writer) +57
   System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +32
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   System.Web.UI.WebControls.WebControl.RenderContents(HtmlTextWriter writer) +10
   System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +32
   System.Web.UI.WebControls.FormViewRow.Render(HtmlTextWriter writer) +38
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.WebControls.Table.RenderContents(HtmlTextWriter writer) +211
   System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +32
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   System.Web.UI.WebControls.WebControl.RenderContents(HtmlTextWriter writer) +10
   System.Web.UI.WebControls.FormView.Render(HtmlTextWriter writer) +86
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   System.Web.UI.Control.Render(HtmlTextWriter writer) +10
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +102
   System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +32
   System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +53
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +40
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   System.Web.UI.Control.Render(HtmlTextWriter writer) +10
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +128
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8
   System.Web.UI.Page.Render(HtmlTextWriter writer) +29
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1386




--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.18446  

Answer 1

你说的我都试过了，还是不行。但是，我发现了一个解决方法，不知为何，它起作用了。我将此添加到我的 web.config 文件中:

 <add key="PageInspector:ServerCodeMappingSupport" value="Disabled" />

它对我有用:D