Question

c#下 mapx添加动态图层

刚刚接触mapx，在网上找到的代码
private void button1_Click(object sender, EventArgs e)
{
MapXLib.LayerInfoClass li = new MapXLib.LayerInfoClass();
MapXLib.Features ftrs = null;
MapXLib.FieldsClass flds = new MapXLib.FieldsClass();
MapXLib.Fields Myflds = null;
MapXLib.Dataset dts = null;
flds.Add("State", "State_Name", MapXLib.AggregationFunctionConstants.miAggregationSum, MapXLib.FieldTypeConstants.miTypeString);
dts = axMap1.DataSets.Add(MapXLib.DatasetTypeConstants.miDataSetLayer, axMap1.Layers._Item(1), "MyLayer", 0, 0, 0, flds, false);
Myflds = dts.Fields;
ftrs = axMap1.Layers._Item("USA").Selection.Clone();
li.Type = MapXLib.LayerInfoTypeConstants.miLayerInfoTypeTemp;
li.AddParameter("Name", "USA Temp Layer");
li.AddParameter("Fields", Myflds);
li.AddParameter("Features", ftrs);
axMap1.Layers.Add(li, 1);
axMap1.Layers.LayersDlg("", "");
}

为什么我每次运行到 dts = axMap1.DataSets.Add(MapXLib.DatasetTypeConstants.miDataSetLayer, axMap1.Layers._Item(1), "MyLayer", 0, 0, 0, flds, false);这一句就弹出错误呢。
错误信息：
An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll
Additional information: No object was found using the index you specified.

Answer 1

private void button1_Click(object sender, EventArgs e)
{
MapXLib.LayerInfoClass li = new MapXLib.LayerInfoClass();
MapXLib.Features ftrs = null;
MapXLib.FieldsClass flds = new MapXLib.FieldsClass();
MapXLib.Fields Myflds = null;
MapXLib.Dataset dts = null;
flds.Add(1,"State_Name", MapXLib.AggregationFunctionConstants.miAggregationSum, MapXLib.FieldTypeConstants.miTypeString);
dts = axMap1.DataSets.Add(MapXLib.DatasetTypeConstants.miDataSetLayer, axMap1.Layers._Item(1), "MyLayer", 0, 0, 0, flds, false);
Myflds = dts.Fields;
ftrs = axMap1.Layers._Item("USA").Selection.Clone();
li.Type = MapXLib.LayerInfoTypeConstants.miLayerInfoTypeTemp;
li.AddParameter("Name", "USA Temp Layer");
li.AddParameter("Fields", Myflds);
li.AddParameter("Features", ftrs);
axMap1.Layers.Add(li, 1);
axMap1.Layers.LayersDlg("", "");
}

Answer 2

对不起，不知道