Olarak çıkıyor uygun bir tip belirlenebilir zaman sonra doğru yazılmış sütunlarla bu sütunları yerine belirsiz veri türleri içeren sütunlar hatırlayarak akış davranışı korurken, doğru sütun türünü ayarlamak mümkündür:
/// <summary>
/// Converts a <see cref="DataTable"/> to and from JSON.
/// </summary>
public class TypeInferringDataTableConverter : Newtonsoft.Json.Converters.DataTableConverter
{
// Adapted from https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Converters/DataTableConverter.cs
// Original license: https://github.com/JamesNK/Newtonsoft.Json/blob/master/LICENSE.md
/// <summary>
/// Reads the JSON representation of the object.
/// </summary>
/// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
/// <param name="objectType">Type of the object.</param>
/// <param name="existingValue">The existing value of object being read.</param>
/// <param name="serializer">The calling serializer.</param>
/// <returns>The object value.</returns>
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
{
return null;
}
DataTable dt = existingValue as DataTable;
if (dt == null)
{
// handle typed datasets
dt = (objectType == typeof(DataTable))
? new DataTable()
: (DataTable)Activator.CreateInstance(objectType);
}
// DataTable is inside a DataSet
// populate the name from the property name
if (reader.TokenType == JsonToken.PropertyName)
{
dt.TableName = (string)reader.Value;
reader.ReadAndAssert();
if (reader.TokenType == JsonToken.Null)
{
return dt;
}
}
if (reader.TokenType != JsonToken.StartArray)
{
throw JsonSerializationExceptionHelper.Create(reader, "Unexpected JSON token when reading DataTable. Expected StartArray, got {0}.".FormatWith(CultureInfo.InvariantCulture, reader.TokenType));
}
reader.ReadAndAssert();
var ambiguousColumnTypes = new HashSet<string>();
while (reader.TokenType != JsonToken.EndArray)
{
CreateRow(reader, dt, serializer, ambiguousColumnTypes);
reader.ReadAndAssert();
}
return dt;
}
private static void CreateRow(JsonReader reader, DataTable dt, JsonSerializer serializer, HashSet<string> ambiguousColumnTypes)
{
DataRow dr = dt.NewRow();
reader.ReadAndAssert();
while (reader.TokenType == JsonToken.PropertyName)
{
string columnName = (string)reader.Value;
reader.ReadAndAssert();
DataColumn column = dt.Columns[columnName];
if (column == null)
{
bool isAmbiguousType;
Type columnType = GetColumnDataType(reader, out isAmbiguousType);
column = new DataColumn(columnName, columnType);
dt.Columns.Add(column);
if (isAmbiguousType)
ambiguousColumnTypes.Add(columnName);
}
else if (ambiguousColumnTypes.Contains(columnName))
{
bool isAmbiguousType;
Type newColumnType = GetColumnDataType(reader, out isAmbiguousType);
if (!isAmbiguousType)
ambiguousColumnTypes.Remove(columnName);
if (newColumnType != column.DataType)
{
column = ReplaceColumn(dt, column, newColumnType, serializer);
}
}
if (column.DataType == typeof(DataTable))
{
if (reader.TokenType == JsonToken.StartArray)
{
reader.ReadAndAssert();
}
DataTable nestedDt = new DataTable();
var nestedUnknownColumnTypes = new HashSet<string>();
while (reader.TokenType != JsonToken.EndArray)
{
CreateRow(reader, nestedDt, serializer, nestedUnknownColumnTypes);
reader.ReadAndAssert();
}
dr[columnName] = nestedDt;
}
else if (column.DataType.IsArray && column.DataType != typeof(byte[]))
{
if (reader.TokenType == JsonToken.StartArray)
{
reader.ReadAndAssert();
}
List<object> o = new List<object>();
while (reader.TokenType != JsonToken.EndArray)
{
o.Add(reader.Value);
reader.ReadAndAssert();
}
Array destinationArray = Array.CreateInstance(column.DataType.GetElementType(), o.Count);
Array.Copy(o.ToArray(), destinationArray, o.Count);
dr[columnName] = destinationArray;
}
else
{
object columnValue = (reader.Value != null)
? serializer.Deserialize(reader, column.DataType) ?? DBNull.Value
: DBNull.Value;
dr[columnName] = columnValue;
}
reader.ReadAndAssert();
}
dr.EndEdit();
dt.Rows.Add(dr);
}
static object RemapValue(object oldValue, Type newType, JsonSerializer serializer)
{
if (oldValue == null)
return null;
if (oldValue == DBNull.Value)
return oldValue;
return JToken.FromObject(oldValue, serializer).ToObject(newType, serializer);
}
private static DataColumn ReplaceColumn(DataTable dt, DataColumn column, Type newColumnType, JsonSerializer serializer)
{
var newValues = Enumerable.Range(0, dt.Rows.Count).Select(i => dt.Rows[i]).Select(r => RemapValue(r[column], newColumnType, serializer)).ToList();
var ordinal = column.Ordinal;
var name = column.ColumnName;
var @namespace = column.Namespace;
var newColumn = new DataColumn(name, newColumnType);
newColumn.Namespace = @namespace;
dt.Columns.Remove(column);
dt.Columns.Add(newColumn);
newColumn.SetOrdinal(ordinal);
for (int i = 0; i < dt.Rows.Count; i++)
dt.Rows[i][newColumn] = newValues[i];
return newColumn;
}
private static Type GetColumnDataType(JsonReader reader, out bool isAmbiguous)
{
JsonToken tokenType = reader.TokenType;
switch (tokenType)
{
case JsonToken.Integer:
case JsonToken.Boolean:
case JsonToken.Float:
case JsonToken.String:
case JsonToken.Date:
case JsonToken.Bytes:
isAmbiguous = false;
return reader.ValueType;
case JsonToken.Null:
case JsonToken.Undefined:
isAmbiguous = true;
return typeof(string);
case JsonToken.StartArray:
reader.ReadAndAssert();
if (reader.TokenType == JsonToken.StartObject)
{
isAmbiguous = false;
return typeof(DataTable); // nested datatable
}
else
{
isAmbiguous = false;
bool innerAmbiguous;
// Handling ambiguity in array entries is not yet implemented because the first non-ambiguous entry in the array
// might occur anywhere in the sequence, requiring us to scan the entire array to determine the type,
// e.g., given: [null, null, null, 314, null]
// we would need to scan until the 314 value, and do:
// return typeof(Nullable<>).MakeGenericType(new[] { reader.ValueType }).MakeArrayType();
Type arrayType = GetColumnDataType(reader, out innerAmbiguous);
return arrayType.MakeArrayType();
}
default:
throw JsonSerializationExceptionHelper.Create(reader, "Unexpected JSON token when reading DataTable: {0}".FormatWith(CultureInfo.InvariantCulture, tokenType));
}
}
}
internal static class JsonSerializationExceptionHelper
{
public static JsonSerializationException Create(this JsonReader reader, string format, params object[] args)
{
// Adapted from https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/JsonPosition.cs
var lineInfo = reader as IJsonLineInfo;
var path = (reader == null ? null : reader.Path);
var message = string.Format(CultureInfo.InvariantCulture, format, args);
if (!message.EndsWith(Environment.NewLine, StringComparison.Ordinal))
{
message = message.Trim();
if (!message.EndsWith(".", StringComparison.Ordinal))
message += ".";
message += " ";
}
message += string.Format(CultureInfo.InvariantCulture, "Path '{0}'", path);
if (lineInfo != null && lineInfo.HasLineInfo())
message += string.Format(CultureInfo.InvariantCulture, ", line {0}, position {1}", lineInfo.LineNumber, lineInfo.LinePosition);
message += ".";
return new JsonSerializationException(message);
}
}
internal static class StringUtils
{
// Adapted from https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Utilities/StringUtils.cs
public static string FormatWith(this string format, IFormatProvider provider, object arg0)
{
return format.FormatWith(provider, new[] { arg0 });
}
private static string FormatWith(this string format, IFormatProvider provider, params object[] args)
{
return string.Format(provider, format, args);
}
}
internal static class JsonReaderExtensions
{
public static void ReadAndAssert(this JsonReader reader)
{
if (reader == null)
throw new ArgumentNullException("reader");
if (!reader.Read())
{
throw JsonSerializationExceptionHelper.Create(reader, "Unexpected end when reading JSON.");
}
}
}
Sonra gibi kullanın:
var settings = new JsonSerializerSettings { Converters = new[] { new TypeInferringDataTableConverter() } };
DataTable tbl1 = Newtonsoft.Json.JsonConvert.DeserializeObject<DataTable>(jsonTable1, settings);
DataTable tbl2 = Newtonsoft.Json.JsonConvert.DeserializeObject<DataTable>(jsonTable2, settings);
belirlemeyin NullValueHandling = NullValueHandling.Ignore nulls doğru şimdi işlenir beri. Bu sınıf null değerleri ile sütun yeniden yazma işleme sırasında, ilk dizi madde boş olduğu dizi değerlerini ihtiva eden sütun yeniden yazmaya işlemez, bu Prototip fiddle
not edin. Örneğin, bazı sütunun ilk satırı Ancak burada uygulanmıyor, değerini Sonra kolon tipi ideal typeof(long? []) olacağını anlaşılmaktadır
[null, null, null, 314, null]
varsa. Bu belirlemeyi yapmak için JSON'u JToken hiyerarşisine tamamen yüklemeniz gerekebilir.
Genel DataTable yerine, seri biçimde yazılan bir nesneyi seri hale getirmeyi dener misiniz? –
İlk önce belirli türlerde bir sınıf oluşturabilir ve json dizesini bu nesnelere serpiştirebilir ve daha sonra veri tabanına dönüştürebilirsiniz. Newtonsoft.Json.JsonConvert.DeserializeObject (jsonTable1); 've daha sonra bu örnek gibi veri tabanına dönüştürün: http: // stackoverflow.com/questions/17088779/fill-datatable-from-linq-query –
@KrishnaChaithanyaMuthyala Veritabanının şemasının dinamik olduğu bir durumdan bahsetmeyi unuttum. Güçlü yazılan sınıf –