Update demo

Src/Asp.Net/SqlServerTest/UnitTest/UCodeFirst.cs

@@ -45,8 +45,17 @@ namespace OrmTest
             { 
             }
             db.CodeFirst.InitTables<UnitTableName>();
+            db.CodeFirst.InitTables<UnitGe>();
+            db.Insertable(new UnitGe() { geometry1 = "POINT (20 180)" }).ExecuteCommand();
+            var gelist=db.Queryable<UnitGe>().Select(it=>new { geometry1 = it.geometry1.ToString()}).ToList();
+        }
 
+        public class UnitGe 
+        {
+            [SugarColumn(ColumnDataType = "geometry")]
+            public string geometry1 { get; set; }
         }
+
         [SugarTable("abp.UnitTableName","备注")]
         public class UnitTableName 
         {

Src/Asp.Net/SqlSugar/Abstract/DbBindProvider/DbBindAccessory.cs

@@ -84,7 +84,10 @@ namespace SqlSugar
             {
                 keys.Add(dataReader.GetName(i));
                 var type = dataReader.GetFieldType(i);
-                sbTypes.Append(type.Name.Substring(0,2));
+                if (type != null)
+                {
+                    sbTypes.Append(type.Name.Substring(0, 2));
+                }
             }
             types = sbTypes.ToString();
             return keys;