DataColumnMapping.cs

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using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Reflection;
 
namespace System.Data.Common;
 
[TypeConverter(typeof(DataColumnMappingConverter))]
public sealed class DataColumnMapping : MarshalByRefObject, IColumnMapping, ICloneable
{
    internal sealed class DataColumnMappingConverter : ExpandableObjectConverter
    {
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (typeof(InstanceDescriptor) == destinationType)
            {
                return true;
            }
            return base.CanConvertTo(context, destinationType);
        }
 
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (null == destinationType)
            {
                throw ADP.ArgumentNull("destinationType");
            }
            if (typeof(InstanceDescriptor) == destinationType && value is DataColumnMapping)
            {
                DataColumnMapping dataColumnMapping = (DataColumnMapping)value;
                object[] arguments = new object[2] { dataColumnMapping.SourceColumn, dataColumnMapping.DataSetColumn };
                Type[] types = new Type[2]
                {
                    typeof(string),
                    typeof(string)
                };
                ConstructorInfo constructor = typeof(DataColumnMapping).GetConstructor(types);
                return new InstanceDescriptor(constructor, arguments);
            }
            return base.ConvertTo(context, culture, value, destinationType);
        }
    }
 
    private DataColumnMappingCollection _parent;
 
    private string _dataSetColumnName;
 
    private string _sourceColumnName;
 
    [DefaultValue("")]
    public string DataSetColumn
    {
        get
        {
            return _dataSetColumnName ?? string.Empty;
        }
        [param: AllowNull]
        set
        {
            _dataSetColumnName = value;
        }
    }
 
    internal DataColumnMappingCollection? Parent
    {
        get
        {
            return _parent;
        }
        set
        {
            _parent = value;
        }
    }
 
    [DefaultValue("")]
    public string SourceColumn
    {
        get
        {
            return _sourceColumnName ?? string.Empty;
        }
        [param: AllowNull]
        set
        {
            if (Parent != null && ADP.SrcCompare(_sourceColumnName, value) != 0)
            {
                Parent.ValidateSourceColumn(-1, value);
            }
            _sourceColumnName = value;
        }
    }
 
    public DataColumnMapping()
    {
    }
 
    public DataColumnMapping(string? sourceColumn, string? dataSetColumn)
    {
        SourceColumn = sourceColumn;
        DataSetColumn = dataSetColumn;
    }
 
    object ICloneable.Clone()
    {
        DataColumnMapping dataColumnMapping = new DataColumnMapping();
        dataColumnMapping._sourceColumnName = _sourceColumnName;
        dataColumnMapping._dataSetColumnName = _dataSetColumnName;
        return dataColumnMapping;
    }
 
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    public DataColumn? GetDataColumnBySchemaAction(DataTable dataTable, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicProperties)] Type? dataType, MissingSchemaAction schemaAction)
    {
        return GetDataColumnBySchemaAction(SourceColumn, DataSetColumn, dataTable, dataType, schemaAction);
    }
 
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    public static DataColumn? GetDataColumnBySchemaAction(string? sourceColumn, string? dataSetColumn, DataTable dataTable, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicProperties)] Type? dataType, MissingSchemaAction schemaAction)
    {
        if (dataTable == null)
        {
            throw ADP.ArgumentNull("dataTable");
        }
        if (string.IsNullOrEmpty(dataSetColumn))
        {
            return null;
        }
        DataColumnCollection columns = dataTable.Columns;
        int num = columns.IndexOf(dataSetColumn);
        if (0 <= num && num < columns.Count)
        {
            DataColumn dataColumn = columns[num];
            if (!string.IsNullOrEmpty(dataColumn.Expression))
            {
                throw ADP.ColumnSchemaExpression(sourceColumn, dataSetColumn);
            }
            if (null == dataType || dataType.IsArray == dataColumn.DataType.IsArray)
            {
                return dataColumn;
            }
            throw ADP.ColumnSchemaMismatch(sourceColumn, dataType, dataColumn);
        }
        return CreateDataColumnBySchemaAction(sourceColumn, dataSetColumn, dataTable, dataType, schemaAction);
    }
 
    internal static DataColumn CreateDataColumnBySchemaAction(string sourceColumn, string dataSetColumn, DataTable dataTable, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.PublicProperties)] Type dataType, MissingSchemaAction schemaAction)
    {
        if (string.IsNullOrEmpty(dataSetColumn))
        {
            return null;
        }
        switch (schemaAction)
        {
        case MissingSchemaAction.Add:
        case MissingSchemaAction.AddWithKey:
            return new DataColumn(dataSetColumn, dataType);
        case MissingSchemaAction.Ignore:
            return null;
        case MissingSchemaAction.Error:
            throw ADP.ColumnSchemaMissing(dataSetColumn, dataTable.TableName, sourceColumn);
        default:
            throw ADP.InvalidMissingSchemaAction(schemaAction);
        }
    }
 
    public override string ToString()
    {
        return SourceColumn;
    }
}