I have to implement GetSchemaTable

Anwind

Well-known member
Joined
Nov 6, 2021
Messages
48
Programming Experience
1-3
I have to implement GetSchemaTable:
C#
public class ListDataReader<T> : IDataReader
        where T : class
{
    #region Private fields
    private IEnumerator<T> _iterator;
    private List<PropertyInfo> _properties = new List<PropertyInfo>();
    #endregion

    #region Public properties
    #endregion

    #region Constructors
    public ListDataReader(IEnumerable<T> list)
    {
        this._iterator = list.GetEnumerator();

        _properties.AddRange(
            typeof(T).GetProperties(
                BindingFlags.GetProperty |
                BindingFlags.Instance |
                BindingFlags.Public |
                BindingFlags.DeclaredOnly
                )
            );
    }
    #endregion

    #region IDataReader implementation
    public int Depth { get; }
    public bool IsClosed { get; }
    public int RecordsAffected { get; }

    public void Close()
    {
        _iterator.Dispose();
    }

    public DataTable GetSchemaTable()
    {
        throw new NotImplementedException();
    }

    public bool NextResult()
    {
        throw new NotImplementedException();
    }

    public bool Read()
    {
        return _iterator.MoveNext();
    }
    #endregion

    #region IDisposable implementation
    public void Dispose()
    {
        Close();
    }
    #endregion

    #region IDataRecord
    public string GetName(int i)
    {
        return _properties[i].Name;
    }

    public string GetDataTypeName(int i)
    {
        throw new NotImplementedException();
    }

    public Type GetFieldType(int i)
    {
        return _properties[i].PropertyType;
    }

    public object GetValue(int i)
    {
        return _properties[i].GetValue(_iterator.Current, null);
    }

    public int GetValues(object[] values)
    {
        int numberOfCopiedValues = Math.Max(_properties.Count, values.Length);

        for (int i = 0; i < numberOfCopiedValues; i++)
        {
            values[i] = GetValue(i);
        }

        return numberOfCopiedValues;
    }

    public int GetOrdinal(string name)
    {
        var index = _properties.FindIndex(p => p.Name == name);

        return index;
    }

    public bool GetBoolean(int i)
    {
        return (bool) GetValue(i);
    }

    public byte GetByte(int i)
    {
        return (byte) GetValue(i);
    }

    public long GetBytes(int i, long fieldOffset, byte[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }

    public char GetChar(int i)
    {
        return (char) GetValue(i);
    }

    public long GetChars(int i, long fieldoffset, char[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }

    public Guid GetGuid(int i)
    {
        return (Guid) GetValue(i);
    }

    public short GetInt16(int i)
    {
        return (short) GetValue(i);
    }

    public int GetInt32(int i)
    {
        return (int) GetValue(i);
    }

    public long GetInt64(int i)
    {
        return (long) GetValue(i);
    }

    public float GetFloat(int i)
    {
        return (float) GetValue(i);
    }

    public double GetDouble(int i)
    {
        return (double) GetValue(i);
    }

    public string GetString(int i)
    {
        return (string) GetValue(i);
    }

    public decimal GetDecimal(int i)
    {
        return (decimal) GetValue(i);
    }

    public DateTime GetDateTime(int i)
    {
        return (DateTime) GetValue(i);
    }

    public IDataReader GetData(int i)
    {
        throw new NotImplementedException();
    }

    public bool IsDBNull(int i)
    {
        return GetValue(i) == null;
    }

    public int FieldCount
    {
        get { return _properties.Count; }
    }

    object IDataRecord.this[int i]
    {
        get { return GetValue(i); }
    }

    object IDataRecord.this[string name]
    {
        get { return GetValue(GetOrdinal(name)); }
    }
    #endregion
}
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public class ListDataReader<T> : IDataReader
        where T : class
{
    #region Private fields
    private IEnumerator<T> _iterator;
    private List<PropertyInfo> _properties = new List<PropertyInfo>();
    #endregion
 
    #region Public properties
    #endregion
 
    #region Constructors
    public ListDataReader(IEnumerable<T> list)
    {
        this._iterator = list.GetEnumerator();
 
        _properties.AddRange(
            typeof(T).GetProperties(
                BindingFlags.GetProperty |
                BindingFlags.Instance |
                BindingFlags.Public |
                BindingFlags.DeclaredOnly
                )
            );
    }
    #endregion
 
    #region IDataReader implementation
    public int Depth { get; }
    public bool IsClosed { get; }
    public int RecordsAffected { get; }
 
    public void Close()
    {
        _iterator.Dispose();
    }
 
    public DataTable GetSchemaTable()
    {
        throw new NotImplementedException();
    }
 
    public bool NextResult()
    {
        throw new NotImplementedException();
    }
 
    public bool Read()
    {
        return _iterator.MoveNext();
    }
    #endregion
 
    #region IDisposable implementation
    public void Dispose()
    {
        Close();
    }
    #endregion
 
    #region IDataRecord
    public string GetName(int i)
    {
        return _properties[i].Name;
    }
 
    public string GetDataTypeName(int i)
    {
        throw new NotImplementedException();
    }
 
    public Type GetFieldType(int i)
    {
        return _properties[i].PropertyType;
    }
 
    public object GetValue(int i)
    {
        return _properties[i].GetValue(_iterator.Current, null);
    }
 
    public int GetValues(object[] values)
    {
        int numberOfCopiedValues = Math.Max(_properties.Count, values.Length);
 
        for (int i = 0; i < numberOfCopiedValues; i++)
        {
            values[i] = GetValue(i);
        }
 
        return numberOfCopiedValues;
    }
 
    public int GetOrdinal(string name)
    {
        var index = _properties.FindIndex(p => p.Name == name);
 
        return index;
    }
 
    public bool GetBoolean(int i)
    {
        return (bool) GetValue(i);
    }
 
    public byte GetByte(int i)
    {
        return (byte) GetValue(i);
    }
 
    public long GetBytes(int i, long fieldOffset, byte[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }
 
    public char GetChar(int i)
    {
        return (char) GetValue(i);
    }
 
    public long GetChars(int i, long fieldoffset, char[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }
 
    public Guid GetGuid(int i)
    {
        return (Guid) GetValue(i);
    }
 
    public short GetInt16(int i)
    {
        return (short) GetValue(i);
    }
 
    public int GetInt32(int i)
    {
        return (int) GetValue(i);
    }
 
    public long GetInt64(int i)
    {
        return (long) GetValue(i);
    }
 
    public float GetFloat(int i)
    {
        return (float) GetValue(i);
    }
 
    public double GetDouble(int i)
    {
        return (double) GetValue(i);
    }
 
    public string GetString(int i)
    {
        return (string) GetValue(i);
    }
 
    public decimal GetDecimal(int i)
    {
        return (decimal) GetValue(i);
    }
 
    public DateTime GetDateTime(int i)
    {
        return (DateTime) GetValue(i);
    }
 
    public IDataReader GetData(int i)
    {
        throw new NotImplementedException();
    }
 
    public bool IsDBNull(int i)
    {
        return GetValue(i) == null;
    }
 
    public int FieldCount
    {
        get { return _properties.Count; }
    }
 
    object IDataRecord.this[int i]
    {
        get { return GetValue(i); }
    }
 
    object IDataRecord.this[string name]
    {
        get { return GetValue(GetOrdinal(name)); }
    }
    #endregion
}

C#:
using (IDataReader reader = new ListDataReader<Client>(clients))
{
    while (reader.Read())
    {
        ...
}


I have to implement GetSchemaTable Function.
Please Teach me. PLEASE...
 
Last edited:
I have to implement GetSchemaTable:
C#
public class ListDataReader<T> : IDataReader
        where T : class
{
    #region Private fields
    private IEnumerator<T> _iterator;
    private List<PropertyInfo> _properties = new List<PropertyInfo>();
    #endregion

    #region Public properties
    #endregion

    #region Constructors
    public ListDataReader(IEnumerable<T> list)
    {
        this._iterator = list.GetEnumerator();

        _properties.AddRange(
            typeof(T).GetProperties(
                BindingFlags.GetProperty |
                BindingFlags.Instance |
                BindingFlags.Public |
                BindingFlags.DeclaredOnly
                )
            );
    }
    #endregion

    #region IDataReader implementation
    public int Depth { get; }
    public bool IsClosed { get; }
    public int RecordsAffected { get; }

    public void Close()
    {
        _iterator.Dispose();
    }

    public DataTable GetSchemaTable()
    {
        throw new NotImplementedException();
    }

    public bool NextResult()
    {
        throw new NotImplementedException();
    }

    public bool Read()
    {
        return _iterator.MoveNext();
    }
    #endregion

    #region IDisposable implementation
    public void Dispose()
    {
        Close();
    }
    #endregion

    #region IDataRecord
    public string GetName(int i)
    {
        return _properties[i].Name;
    }

    public string GetDataTypeName(int i)
    {
        throw new NotImplementedException();
    }

    public Type GetFieldType(int i)
    {
        return _properties[i].PropertyType;
    }

    public object GetValue(int i)
    {
        return _properties[i].GetValue(_iterator.Current, null);
    }

    public int GetValues(object[] values)
    {
        int numberOfCopiedValues = Math.Max(_properties.Count, values.Length);

        for (int i = 0; i < numberOfCopiedValues; i++)
        {
            values[i] = GetValue(i);
        }

        return numberOfCopiedValues;
    }

    public int GetOrdinal(string name)
    {
        var index = _properties.FindIndex(p => p.Name == name);

        return index;
    }

    public bool GetBoolean(int i)
    {
        return (bool) GetValue(i);
    }

    public byte GetByte(int i)
    {
        return (byte) GetValue(i);
    }

    public long GetBytes(int i, long fieldOffset, byte[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }

    public char GetChar(int i)
    {
        return (char) GetValue(i);
    }

    public long GetChars(int i, long fieldoffset, char[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }

    public Guid GetGuid(int i)
    {
        return (Guid) GetValue(i);
    }

    public short GetInt16(int i)
    {
        return (short) GetValue(i);
    }

    public int GetInt32(int i)
    {
        return (int) GetValue(i);
    }

    public long GetInt64(int i)
    {
        return (long) GetValue(i);
    }

    public float GetFloat(int i)
    {
        return (float) GetValue(i);
    }

    public double GetDouble(int i)
    {
        return (double) GetValue(i);
    }

    public string GetString(int i)
    {
        return (string) GetValue(i);
    }

    public decimal GetDecimal(int i)
    {
        return (decimal) GetValue(i);
    }

    public DateTime GetDateTime(int i)
    {
        return (DateTime) GetValue(i);
    }

    public IDataReader GetData(int i)
    {
        throw new NotImplementedException();
    }

    public bool IsDBNull(int i)
    {
        return GetValue(i) == null;
    }

    public int FieldCount
    {
        get { return _properties.Count; }
    }

    object IDataRecord.this[int i]
    {
        get { return GetValue(i); }
    }

    object IDataRecord.this[string name]
    {
        get { return GetValue(GetOrdinal(name)); }
    }
    #endregion
}
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public class ListDataReader<T> : IDataReader
        where T : class
{
    #region Private fields
    private IEnumerator<T> _iterator;
    private List<PropertyInfo> _properties = new List<PropertyInfo>();
    #endregion
 
    #region Public properties
    #endregion
 
    #region Constructors
    public ListDataReader(IEnumerable<T> list)
    {
        this._iterator = list.GetEnumerator();
 
        _properties.AddRange(
            typeof(T).GetProperties(
                BindingFlags.GetProperty |
                BindingFlags.Instance |
                BindingFlags.Public |
                BindingFlags.DeclaredOnly
                )
            );
    }
    #endregion
 
    #region IDataReader implementation
    public int Depth { get; }
    public bool IsClosed { get; }
    public int RecordsAffected { get; }
 
    public void Close()
    {
        _iterator.Dispose();
    }
 
    public DataTable GetSchemaTable()
    {
        throw new NotImplementedException();
    }
 
    public bool NextResult()
    {
        throw new NotImplementedException();
    }
 
    public bool Read()
    {
        return _iterator.MoveNext();
    }
    #endregion
 
    #region IDisposable implementation
    public void Dispose()
    {
        Close();
    }
    #endregion
 
    #region IDataRecord
    public string GetName(int i)
    {
        return _properties[i].Name;
    }
 
    public string GetDataTypeName(int i)
    {
        throw new NotImplementedException();
    }
 
    public Type GetFieldType(int i)
    {
        return _properties[i].PropertyType;
    }
 
    public object GetValue(int i)
    {
        return _properties[i].GetValue(_iterator.Current, null);
    }
 
    public int GetValues(object[] values)
    {
        int numberOfCopiedValues = Math.Max(_properties.Count, values.Length);
 
        for (int i = 0; i < numberOfCopiedValues; i++)
        {
            values[i] = GetValue(i);
        }
 
        return numberOfCopiedValues;
    }
 
    public int GetOrdinal(string name)
    {
        var index = _properties.FindIndex(p => p.Name == name);
 
        return index;
    }
 
    public bool GetBoolean(int i)
    {
        return (bool) GetValue(i);
    }
 
    public byte GetByte(int i)
    {
        return (byte) GetValue(i);
    }
 
    public long GetBytes(int i, long fieldOffset, byte[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }
 
    public char GetChar(int i)
    {
        return (char) GetValue(i);
    }
 
    public long GetChars(int i, long fieldoffset, char[] buffer, int bufferoffset, int length)
    {
        throw new NotImplementedException();
    }
 
    public Guid GetGuid(int i)
    {
        return (Guid) GetValue(i);
    }
 
    public short GetInt16(int i)
    {
        return (short) GetValue(i);
    }
 
    public int GetInt32(int i)
    {
        return (int) GetValue(i);
    }
 
    public long GetInt64(int i)
    {
        return (long) GetValue(i);
    }
 
    public float GetFloat(int i)
    {
        return (float) GetValue(i);
    }
 
    public double GetDouble(int i)
    {
        return (double) GetValue(i);
    }
 
    public string GetString(int i)
    {
        return (string) GetValue(i);
    }
 
    public decimal GetDecimal(int i)
    {
        return (decimal) GetValue(i);
    }
 
    public DateTime GetDateTime(int i)
    {
        return (DateTime) GetValue(i);
    }
 
    public IDataReader GetData(int i)
    {
        throw new NotImplementedException();
    }
 
    public bool IsDBNull(int i)
    {
        return GetValue(i) == null;
    }
 
    public int FieldCount
    {
        get { return _properties.Count; }
    }
 
    object IDataRecord.this[int i]
    {
        get { return GetValue(i); }
    }
 
    object IDataRecord.this[string name]
    {
        get { return GetValue(GetOrdinal(name)); }
    }
    #endregion
}

C#:
using (IDataReader reader = new ListDataReader<Client>(clients))
{
    while (reader.Read())
    {
        ...
}


I have to implement GetSchemaTable Function.
Please Teach me. PLEASE...

You put little to no effort into looking for the answer, and it is painfully obvious. Why bother learning how to code if you refuse to do the work?
 
What is the actual problem? You should know that every time you say "please teach me" it is so annoying that you make it less likely that anyone will help. I'm giving you one more chance. Don't just dump a big wad of code and say "please teach me". Explain your specific problem. Do you understand what GetSchemaTable is supposed to do? What exactly are you starting with? What do you understand and what not? Have you looked at the implementation for other data readers? Be specific.
 
If a Nissan engineer could just copy and paste code from StackOverflow and put it into multiple Nissan on-screen displays, and get paid big bucks for it, why not other developers? :)
 
I've often said that my co didn't hire a developer, they just hired a semi-intelligent adapter between google and their problem
 

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