问为什么无法导出动态列?如何解决?只能导出固定列

<div class="mx-0 px-0" >

<MCard Class="mt-5 pb-5">

<MTabs Value="tabIndex" ValueChanged="args => TabChange(args)">

@foreach (var key in tabs.Keys)

{

<MTab Value="key">

@tabs[key]

</MTab>

}

</MTabs>

<MTabsItems Value="@tabIndex">

<MTabItem Value="1">

<StandardInfo Class="mt-5" Type="1" Item="_subjectAnalysisDTO"></StandardInfo>

</MTabItem>

<MTabItem Value="0">

<StandardInfo Class="mt-5" Type="0" Item="_subjectAnalysisDTO"></StandardInfo>

</MTabItem>

</MTabsItems>

<div class="grid-container my-5 mx-5">

<DxGrid @ref="Grid2"

Data="@cls列表导出"

ColumnResizeMode="GridColumnResizeMode.NextColumn"

TextWrapEnabled="true"

HighlightRowOnHover="true"

PageSize="20">

<Columns>

<DxGridDataColumn FieldName="姓名" Width="100px" />

<DxGridDataColumn FieldName="部门" Width="100px" />

<DxGridDataColumn FieldName="工号" Width="150px" />

<DxGridDataColumn FieldName="岗位" Width="100px" />

<DxGridDataColumn FieldName="项目名称" Width="100px" />

<DxGridDataColumn FieldName="总完成数" Width="100px" />

<DxGridDataColumn FieldName="总进度" Width="100px" />

<DxGridBandColumn Caption="任务明细" Width="100px">

<Columns>

@* 任务生成 *@

@foreach (var stageName in 任务列表导出)

{

<DxGridDataColumn Caption="@stageName" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.任务数据列表?.FirstOrDefault(s => s.任务名称 == stageName);

@(stageData?.任务状态 ?? "-")

}

</CellDisplayTemplate>

</DxGridDataColumn>

}

</Columns>

</DxGridBandColumn>

@* 阶段生成 *@

@foreach (var stageName in 所有阶段列表导出)

{

<DxGridBandColumn Caption="@stageName" Width="100px">

<Columns>

<DxGridDataColumn Caption="开始时间" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

@(stageData?.开始时间 ?? "-")

}

</CellDisplayTemplate>

</DxGridDataColumn>

<DxGridDataColumn Caption="结束时间" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

@(stageData?.结束时间 ?? "-")

}

</CellDisplayTemplate>

</DxGridDataColumn>

<DxGridDataColumn Caption="首次学习" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

@(stageData?.首次学习时间 ?? "-")

}

</CellDisplayTemplate>

</DxGridDataColumn>

<DxGridDataColumn Caption="最近学习" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

@(stageData?.最近学习时间 ?? "-")

}

</CellDisplayTemplate>

</DxGridDataColumn>

<DxGridDataColumn Caption="阶段合格" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

<span class="@(stageData?.阶段合格)">

@(stageData?.阶段合格)

</span>

}

</CellDisplayTemplate>

</DxGridDataColumn>

<DxGridDataColumn Caption="阶段状态" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

<span class="@(stageData?.阶段状态)">

@(stageData?.阶段状态 ?? "未开始")

</span>

}

</CellDisplayTemplate>

</DxGridDataColumn>

<DxGridDataColumn Caption="阶段完成数" Width="100px">

<CellDisplayTemplate Context="context">

@{

var item = (cls导出)context.DataItem;

var stageData = item.阶段数据列表导出?.FirstOrDefault(s => s.阶段名称 == stageName);

@(stageData?.阶段完成数 ?? "0")

}

</CellDisplayTemplate>

</DxGridDataColumn>

</Columns>

</DxGridBandColumn>

}

</Columns>

<ToolbarTemplate>

<DxToolbar>

<DxToolbarItem Text="导出Excel" IconCssClass="dx-icon-exportxlsx" Click="ExportXlsx_Click导出" />

</DxToolbar>

</ToolbarTemplate>

</DxGrid>

</div>

</MCard>

</div>

private async Task ExportXlsx_Click导出()

{

if (Grid2 == null) return;

try

{

Grid2.Reload();

await Grid2.ExportToXlsxAsync($"学习进度详细报表_{DateTime.Now:yyyyMMdd_HHmmss}");

}

catch (Exception ex)

{

Console.WriteLine($"导出失败: {ex.Message}");

}

}