已修改完成，同时解决了“考生名单都是 0 人”的根因。

考生范围统一为“行政班关联学生 + 已选课学生”，并自动去重；考场分配、人数显示、冲突检测、学生考试安排均使用同一口径。[TeachingTaskRosterQuery.cs (line 40)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/Teaching/TeachingTaskRosterQuery.cs:40)
新增考场签名单 Excel 导出接口。[ExamsController.cs (line 568)](E:/jiaowu/src/Jiaowu.Api/Controllers/ExamsController.cs:568)
考试计划页面新增“导出考场签名单”按钮。[ExamsView.vue (line 255)](E:/jiaowu/web/src/views/ExamsView.vue:255)
工作簿包含“考场汇总”以及每个考试场次独立的 A4 签到表，字段包括座位号、学号、姓名、行政班、考生签名和备注。[ExamSignInWorkbookExporter.cs (line 12)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/Exams/ExamSignInWorkbookExporter.cs:12)
未分配考场或监考教师时，也能导出并显示“待分配”。

src/Jiaowu.Api/Infrastructure/Teaching/TeachingTaskRosterQuery.cs

@@ -1,5 +1,6 @@
 using Jiaowu.Api.Domain.Academic;
 using Jiaowu.Api.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
 
 namespace Jiaowu.Api.Infrastructure.Teaching;
 
@@ -15,4 +16,107 @@ public static class TeachingTaskRosterQuery
                 enrollment.StudentId == student.Id &&
                 enrollment.Status == CourseEnrollmentStatus.Enrolled &&
                 enrollment.CourseSelectionOffering!.TeachingTaskId == teachingTaskId));
+
+    public static IQueryable<Guid> TaskIdsForStudent(AppDbContext db, Guid studentId)
+    {
+        var classTaskIds = db.Students
+            .Where(student =>
+                student.Id == studentId &&
+                student.Status == StudentStatus.Active)
+            .SelectMany(student => db.TeachingTaskClasses
+                .Where(assignment =>
+                    assignment.AdministrativeClassId ==
+                    student.AdministrativeClassId)
+                .Select(assignment => assignment.TeachingTaskId));
+        var enrolledTaskIds = db.CourseEnrollments
+            .Where(enrollment =>
+                enrollment.StudentId == studentId &&
+                enrollment.Status == CourseEnrollmentStatus.Enrolled)
+            .Select(enrollment =>
+                enrollment.CourseSelectionOffering!.TeachingTaskId);
+        return classTaskIds.Concat(enrolledTaskIds).Distinct();
+    }
+
+    public static async Task<IReadOnlyList<TeachingTaskRosterEntry>> LoadForTasksAsync(
+        AppDbContext db,
+        IEnumerable<Guid> teachingTaskIds,
+        CancellationToken cancellationToken)
+    {
+        var taskIds = teachingTaskIds.Distinct().ToArray();
+        if (taskIds.Length == 0) return [];
+
+        var assignments = await db.TeachingTaskClasses.AsNoTracking()
+            .WhereIn(taskIds, x => x.TeachingTaskId)
+            .Select(x => new
+            {
+                x.TeachingTaskId,
+                x.AdministrativeClassId
+            })
+            .ToListAsync(cancellationToken);
+
+        var classIds = assignments
+            .Select(x => x.AdministrativeClassId)
+            .Distinct()
+            .ToArray();
+        var classStudents = classIds.Length == 0
+            ? []
+            : await db.Students.AsNoTracking()
+                .Where(x => x.Status == StudentStatus.Active)
+                .WhereIn(classIds, x => x.AdministrativeClassId)
+                .Select(x => new RosterStudent(
+                    x.Id,
+                    x.StudentNumber,
+                    x.Name,
+                    x.AdministrativeClassId,
+                    x.AdministrativeClass!.Name))
+                .ToListAsync(cancellationToken);
+
+        var enrolledStudents = await db.CourseEnrollments.AsNoTracking()
+            .Where(x => x.Status == CourseEnrollmentStatus.Enrolled)
+            .WhereIn(taskIds, x => x.CourseSelectionOffering!.TeachingTaskId)
+            .Select(x => new TeachingTaskRosterEntry(
+                x.CourseSelectionOffering!.TeachingTaskId,
+                x.StudentId,
+                x.Student!.StudentNumber,
+                x.Student.Name,
+                x.Student.AdministrativeClass!.Name))
+            .ToListAsync(cancellationToken);
+
+        var result = enrolledStudents.ToDictionary(
+            x => (x.TeachingTaskId, x.StudentId));
+        var studentsByClass = classStudents.ToLookup(x => x.AdministrativeClassId);
+        foreach (var assignment in assignments)
+        {
+            foreach (var student in studentsByClass[assignment.AdministrativeClassId])
+            {
+                result.TryAdd(
+                    (assignment.TeachingTaskId, student.StudentId),
+                    new TeachingTaskRosterEntry(
+                        assignment.TeachingTaskId,
+                        student.StudentId,
+                        student.StudentNumber,
+                        student.Name,
+                        student.ClassName));
+            }
+        }
+
+        return result.Values
+            .OrderBy(x => x.TeachingTaskId)
+            .ThenBy(x => x.StudentNumber)
+            .ToList();
+    }
+
+    private sealed record RosterStudent(
+        Guid StudentId,
+        string StudentNumber,
+        string Name,
+        Guid AdministrativeClassId,
+        string ClassName);
 }
+
+public sealed record TeachingTaskRosterEntry(
+    Guid TeachingTaskId,
+    Guid StudentId,
+    string StudentNumber,
+    string Name,
+    string ClassName);