create_section_view_group

Code Template

var sampleLineGroupHandle = "SAMPLE_LINE_GROUP_HANDLE";
var insertionX = double.NaN;
var insertionY = double.NaN;
var startStation = double.NaN;
var endStation = double.NaN;
var leftWidth = double.NaN;
var rightWidth = double.NaN;
var sectionViewStyleName = "";
var bandSetStyleName = "";
var bandSources = new (int bandIndex, string section1SourceHandle, string section2SourceHandle, bool showLabels)[] { };
var templatePath = "";
var layoutName = "";
var groupPlotStyleName = "";
var viewNamePrefix = "";
var nameDecimals = 2;
var nameIntegerDigits = 3;

var isHandle = new Func<string, bool>(value =>
    !string.IsNullOrWhiteSpace(value)
    && System.Text.RegularExpressions.Regex.IsMatch(value, "^[0-9A-Fa-f]{1,16}$"));
var isOptionalName = new Func<string, bool>(value =>
    value != null && (value == "" || (value == value.Trim() && value.Length <= 255 && !value.Any(char.IsControl))));
if (!isHandle(sampleLineGroupHandle))
    return new { success = false, error = "sampleLineGroupHandle must be a hexadecimal handle." };
if (!double.IsFinite(insertionX) || !double.IsFinite(insertionY))
    return new { success = false, error = "insertionX and insertionY are required." };
if (double.IsInfinity(startStation) || double.IsInfinity(endStation))
    return new { success = false, error = "startStation and endStation must be finite or NaN." };
if (double.IsNaN(leftWidth) != double.IsNaN(rightWidth)
    || (!double.IsNaN(leftWidth) && (!double.IsFinite(leftWidth) || !double.IsFinite(rightWidth)
        || leftWidth <= 0 || rightWidth <= 0 || leftWidth > 1000 || rightWidth > 1000)))
    return new { success = false, error = "Give both leftWidth and rightWidth (greater than 0, at most 1000) or neither." };
if (!isOptionalName(sectionViewStyleName) || !isOptionalName(bandSetStyleName) || !isOptionalName(groupPlotStyleName)
    || !isOptionalName(layoutName) || templatePath == null || templatePath.Length > 1024 || templatePath.Any(char.IsControl))
    return new { success = false, error = "Style, layout and template names must be empty or trimmed names." };
if ((templatePath == "") != (layoutName == ""))
    return new { success = false, error = "Give templatePath and layoutName together for production placement, or neither for draft placement." };
if (viewNamePrefix == null || viewNamePrefix.Length > 100 || viewNamePrefix.Any(char.IsControl)
    || nameDecimals < 0 || nameDecimals > 4 || nameIntegerDigits < 0 || nameIntegerDigits > 6)
    return new { success = false, error = "viewNamePrefix must be at most 100 characters, nameDecimals 0..4 and nameIntegerDigits 0..6." };
if (bandSources == null || bandSources.Length > 20
    || bandSources.Any(b => b.bandIndex < 0 || b.bandIndex > 19
        || b.section1SourceHandle == null || b.section2SourceHandle == null
        || (b.section1SourceHandle != "" && !isHandle(b.section1SourceHandle))
        || (b.section2SourceHandle != "" && !isHandle(b.section2SourceHandle)))
    || bandSources.Select(b => b.bandIndex).Distinct().Count() != bandSources.Length)
    return new { success = false, error = "bandSources needs distinct band indexes 0..19 with empty or hexadecimal source handles." };

ObjectId? ResolveId(string handle)
{
    try { return Database.GetObjectId(false, new Handle(System.Convert.ToInt64(handle, 16)), 0); }
    catch { return null; }
}

var groupId = ResolveId(sampleLineGroupHandle);
var group = groupId.HasValue ? Transaction.GetObject(groupId.Value, OpenMode.ForRead) as SampleLineGroup : null;
if (group == null || group.IsErased || group.IsReferenceObject)
    return new { success = false, error = "sampleLineGroupHandle must identify an existing local sample line group." };

var lines = new List<SampleLine>();
foreach (ObjectId id in group.GetSampleLineIds())
    if (Transaction.GetObject(id, OpenMode.ForRead) is SampleLine line && !line.IsErased) lines.Add(line);
if (lines.Count == 0)
    return new { success = false, error = "The sample line group has no sample lines." };
var firstStation = double.IsNaN(startStation) ? lines.Min(l => l.Station) : startStation;
var lastStation = double.IsNaN(endStation) ? lines.Max(l => l.Station) : endStation;
var selected = lines.Where(l => l.Station >= firstStation - 1e-6 && l.Station <= lastStation + 1e-6)
    .OrderBy(l => l.Station).ToList();
if (lastStation < firstStation || selected.Count == 0 || selected.Count > 1000)
    return new { success = false, error = "The station range must select 1 to 1000 sample lines.", selected = selected.Count };

ObjectId LookupStyle(Func<ObjectId> lookup)
{
    try { return lookup(); }
    catch { return ObjectId.Null; }
}
var viewStyleId = sectionViewStyleName == "" ? ObjectId.Null : LookupStyle(() => CivilDoc.Styles.SectionViewStyles[sectionViewStyleName]);
var bandSetId = bandSetStyleName == "" ? ObjectId.Null : LookupStyle(() => CivilDoc.Styles.SectionViewBandSetStyles[bandSetStyleName]);
var plotStyleId = groupPlotStyleName == "" ? ObjectId.Null : LookupStyle(() => CivilDoc.Styles.GroupPlotStyles[groupPlotStyleName]);
if ((sectionViewStyleName != "" && viewStyleId.IsNull) || (bandSetStyleName != "" && bandSetId.IsNull)
    || (groupPlotStyleName != "" && plotStyleId.IsNull))
    return new { success = false, error = "A named section view, band set or group plot style does not exist.", sectionViewStyleName, bandSetStyleName, groupPlotStyleName };

// GetSectionSources needs the group open for write; on a read-open group
// Civil 3D 2025 ends with a fatal eNotOpenForWrite. Nothing is changed yet.
group.UpgradeOpen();
// Band sources must be sampled sources of this group.
var sampledSourceIds = new HashSet<ObjectId>();
foreach (SectionSource source in group.GetSectionSources())
    if (source.IsSampled) sampledSourceIds.Add(source.SourceId);
// Null means unchanged; an unknown or unsampled source is rejected.
(bool ok, ObjectId id) BandSource(string handle)
{
    if (handle == "") return (true, ObjectId.Null);
    var id = ResolveId(handle);
    return id.HasValue && sampledSourceIds.Contains(id.Value) ? (true, id.Value) : (false, ObjectId.Null);
}
var bandPlan = new List<(int bandIndex, ObjectId source1, ObjectId source2, bool showLabels)>();
foreach (var band in bandSources)
{
    var source1 = BandSource(band.section1SourceHandle);
    var source2 = BandSource(band.section2SourceHandle);
    if (!source1.ok || !source2.ok)
        return new { success = false, error = "Every band source handle must be a sampled section source of this sample line group.", band.bandIndex };
    bandPlan.Add((band.bandIndex, source1.id, source2.id, band.showLabels));
}

var placement = new SectionViewGroupCreationPlacementOptions();
if (templatePath != "")
{
    string[] layouts;
    try { layouts = placement.GetAvailableLayoutNames(templatePath); }
    catch (System.Exception ex) { return new { success = false, error = "The template could not be read.", templatePath, detail = ex.Message }; }
    if (layouts == null || !layouts.Contains(layoutName))
        return new { success = false, error = "The layout does not exist in the template.", layoutName, available = layouts };
    placement.UseProductionPlacement(templatePath, layoutName);
}
else
{
    placement.UseDraftPlacement();
}

string FormatStation(double station)
{
    var text = Math.Abs(station).ToString("F" + nameDecimals, System.Globalization.CultureInfo.InvariantCulture);
    var dot = text.IndexOf('.');
    var integerPart = dot < 0 ? text : text.Substring(0, dot);
    text = integerPart.PadLeft(nameIntegerDigits, '0') + (dot < 0 ? "" : text.Substring(dot));
    return (station < 0 ? "-" : "") + text;
}
var plannedNames = new Dictionary<ObjectId, string>();
if (viewNamePrefix != "")
{
    var otherNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
    foreach (var line in lines)
        foreach (ObjectId viewId in line.GetSectionViewIds())
            if (Transaction.GetObject(viewId, OpenMode.ForRead) is SectionView view) otherNames.Add(view.Name);
    foreach (var line in selected) plannedNames[line.ObjectId] = viewNamePrefix + FormatStation(line.Station);
    var clashes = plannedNames.Values.GroupBy(n => n, StringComparer.OrdinalIgnoreCase)
        .Where(g => g.Count() > 1 || otherNames.Contains(g.Key)).Select(g => g.Key).ToList();
    if (clashes.Count > 0)
        return new { success = false, error = "View names would collide; raise nameDecimals or change the prefix.", names = clashes };
}

// One native group: group-level editing and sheet placement need it.
// Any failure below throws, so nothing is kept.
SectionViewGroup viewGroup;
using (var range = new SectionViewGroupCreationRangeOptions(group.ObjectId))
{
    if (!double.IsNaN(leftWidth))
    {
        range.SetOffsetRange(-leftWidth, rightWidth);
        range.UseUserSpecifiedOffset = true;
    }
    viewGroup = group.SectionViewGroups.Add(new Point3d(insertionX, insertionY, 0), firstStation, lastStation, range, placement);
}
if (viewGroup == null || viewGroup.IsIndividual)
    throw new InvalidOperationException("Civil 3D did not create a native section view group.");
if (!plotStyleId.IsNull)
{
    viewGroup.PlotStyleId = plotStyleId;
    viewGroup.UpdateLayout();
}

var lineById = selected.ToDictionary(l => l.ObjectId);
var views = new List<(SectionView view, SampleLine line)>();
foreach (ObjectId viewId in viewGroup.GetSectionViewIds())
{
    var view = (SectionView)Transaction.GetObject(viewId, OpenMode.ForWrite);
    if (!lineById.TryGetValue(view.SampleLineId, out var line))
        throw new InvalidOperationException($"View '{view.Name}' belongs to a sample line outside the selected range.");
    views.Add((view, line));
}
if (views.Count != selected.Count || views.Select(v => v.line.ObjectId).Distinct().Count() != selected.Count)
    throw new InvalidOperationException($"Expected one view per selected sample line ({selected.Count}), got {views.Count}.");

foreach (var (view, line) in views)
{
    if (!viewStyleId.IsNull) view.StyleId = viewStyleId;
    if (!bandSetId.IsNull) view.Bands.ImportBandSetStyle(bandSetId);
    if (bandPlan.Count > 0)
    {
        var items = view.Bands.GetBottomBandItems();
        var itemList = items.Cast<SectionViewBandItem>().ToList();
        foreach (var band in bandPlan)
        {
            if (band.bandIndex >= itemList.Count)
                throw new InvalidOperationException($"View '{view.Name}' has {itemList.Count} bottom bands; band {band.bandIndex} does not exist.");
            var item = itemList[band.bandIndex];
            if (!band.source1.IsNull) item.Section1Id = line.GetSectionId(band.source1);
            if (!band.source2.IsNull) item.Section2Id = line.GetSectionId(band.source2);
            item.ShowLabels = band.showLabels;
        }
        view.Bands.SetBottomBandItems(items);
    }
}

// Rename through unique temporary names so swaps cannot collide.
if (plannedNames.Count > 0)
{
    foreach (var (view, line) in views) view.Name = "__tmp_" + view.Handle.ToString();
    foreach (var (view, line) in views) view.Name = plannedNames[line.ObjectId];
}

string SourceName(ObjectId sectionId) =>
    sectionId.IsNull ? null : (Transaction.GetObject(sectionId, OpenMode.ForRead) as Autodesk.Civil.DatabaseServices.Section)?.SourceName;
var ordered = views.OrderBy(v => v.line.Station).ToList();
var firstBands = new List<object>();
var bandIndex = 0;
foreach (SectionViewBandItem item in ordered[0].view.Bands.GetBottomBandItems())
{
    firstBands.Add(new {
        index = bandIndex++,
        type = item.BandType.ToString(),
        section1 = SourceName(item.Section1Id),
        section2 = SourceName(item.Section2Id),
        item.ShowLabels
    });
}
var steps = ordered.Zip(ordered.Skip(1), (a, b) => b.view.Location.X - a.view.Location.X).ToList();

return new {
    success = true,
    sampleLineGroup = new { name = group.Name, handle = group.Handle.ToString() },
    viewGroup = new {
        name = viewGroup.Name,
        isIndividual = viewGroup.IsIndividual,
        templatePath = viewGroup.TemplateFilePath,
        layoutName = viewGroup.LayoutName,
        viewCount = views.Count
    },
    stationRange = new { first = firstStation, last = lastStation },
    leftToRightByStation = steps.All(step => step > 0),
    views = ordered.Select(v => new {
        name = v.view.Name,
        handle = v.view.Handle.ToString(),
        sampleLine = v.line.Name,
        station = v.line.Station,
        x = v.view.Location.X,
        y = v.view.Location.Y,
        offsetLeft = v.view.OffsetLeft,
        offsetRight = v.view.OffsetRight,
        elevationMin = v.view.ElevationMin,
        elevationMax = v.view.ElevationMax,
        style = v.view.StyleName
    }).ToList(),
    firstViewBottomBands = firstBands
};