C# 扩展自定义Datatable以提供其他方法

我想让它变得简单一点，将

DataRow

集合的值分配给一些对象的属性

我想这样做：

Tabelle t = new Tabelle(query, Id, 1200);

foreach (DataRow r in t.Rows)
{
    CustObject b = new CustObject();

    r.AssingValue(Columnname, b, PropertyName);
}

internal class Tabelle : DataTable
{
    DataTable tabelle = new DataTable();

    internal Tabelle(string abfrage)
    {
        try
        {
            SqlDataAdapter adapter = new SqlDataAdapter((SqlCommand)new Prozedur(abfrage));
            if (adapter.SelectCommand.Connection != null && adapter.SelectCommand.Connection.State == ConnectionState.Open)
            {
                adapter.Fill(this);
            }
        }
    }

    // How can I attach this method to the datarow Collection?
    public void AssingValue(string parametername, object target, string propertyName)
    {
        if (Row.Value != System.DBNull.Value) // how would I access the DataRow Value? 
        {
            var prop = target.GetType().GetProperty(propertyName);
            prop.SetValue(target, Convert.ToDateTime(Row.Value));
        }

    }

}

public void AssingValue(string columnName, object target, string propertyName, int rowIndex)
{
    DataRow row = this.Rows[rowIndex];
    if (row[columnName] != System.DBNull.Value) // how would I access the DataRow Value? 
    {
        var prop = target.GetType().GetProperty(propertyName);
        prop.SetValue(target, Convert.ToDateTime(row[columnName]));
    }

}

该表如下所示：

Tabelle t = new Tabelle(query, Id, 1200);

foreach (DataRow r in t.Rows)
{
    CustObject b = new CustObject();

    r.AssingValue(Columnname, b, PropertyName);
}

internal class Tabelle : DataTable
{
    DataTable tabelle = new DataTable();

    internal Tabelle(string abfrage)
    {
        try
        {
            SqlDataAdapter adapter = new SqlDataAdapter((SqlCommand)new Prozedur(abfrage));
            if (adapter.SelectCommand.Connection != null && adapter.SelectCommand.Connection.State == ConnectionState.Open)
            {
                adapter.Fill(this);
            }
        }
    }

    // How can I attach this method to the datarow Collection?
    public void AssingValue(string parametername, object target, string propertyName)
    {
        if (Row.Value != System.DBNull.Value) // how would I access the DataRow Value? 
        {
            var prop = target.GetType().GetProperty(propertyName);
            prop.SetValue(target, Convert.ToDateTime(Row.Value));
        }

    }

}

public void AssingValue(string columnName, object target, string propertyName, int rowIndex)
{
    DataRow row = this.Rows[rowIndex];
    if (row[columnName] != System.DBNull.Value) // how would I access the DataRow Value? 
    {
        var prop = target.GetType().GetProperty(propertyName);
        prop.SetValue(target, Convert.ToDateTime(row[columnName]));
    }

}

---

Assign方法应具有输入参数，如

rowIndex

以查找表中的特定行，以及

columnName

以获取/设置行的列值

您可以尝试以下方法：

Tabelle t = new Tabelle(query, Id, 1200);

foreach (DataRow r in t.Rows)
{
    CustObject b = new CustObject();

    r.AssingValue(Columnname, b, PropertyName);
}

internal class Tabelle : DataTable
{
    DataTable tabelle = new DataTable();

    internal Tabelle(string abfrage)
    {
        try
        {
            SqlDataAdapter adapter = new SqlDataAdapter((SqlCommand)new Prozedur(abfrage));
            if (adapter.SelectCommand.Connection != null && adapter.SelectCommand.Connection.State == ConnectionState.Open)
            {
                adapter.Fill(this);
            }
        }
    }

    // How can I attach this method to the datarow Collection?
    public void AssingValue(string parametername, object target, string propertyName)
    {
        if (Row.Value != System.DBNull.Value) // how would I access the DataRow Value? 
        {
            var prop = target.GetType().GetProperty(propertyName);
            prop.SetValue(target, Convert.ToDateTime(Row.Value));
        }

    }

}

public void AssingValue(string columnName, object target, string propertyName, int rowIndex)
{
    DataRow row = this.Rows[rowIndex];
    if (row[columnName] != System.DBNull.Value) // how would I access the DataRow Value? 
    {
        var prop = target.GetType().GetProperty(propertyName);
        prop.SetValue(target, Convert.ToDateTime(row[columnName]));
    }

}

---

如果我理解正确，您可以通过datarow类本身的扩展方法来实现这一点

public static class DataRowExtensionMethods
{
    public static int ReturnIntForField(this DataRow data, string fieldName)
    {
        return data[fieldName] == DBNull.Value ? 0 : Convert.ToInt32(data[fieldName]);
    }

    public static DateTime ReturnDateTimeFromDataRowField(this DataRow data, string fieldName)
    {
        return Convert.ToDateTime(data[fieldName]);
    }
} \\etc... etc...

然后，我们可以按照以下步骤重新编写datarow循环

foreach (DataRow r in t.Rows)
{
    CustObject b = new CustObject();
    b.PropertyName = r.ReturnIntForField("ColumnName");         
    b.PropertyName1 = r.ReturnDateTimeFromDataRowField("ColumnName1");
}

---

希望这能有所帮助

谢谢，这很有效。将索引传递回

数据表

，这似乎有点奇怪，因为我分析了同一对象的行集合。我为您提供了另一种解决方案。。如果我理解正确的话！谢谢，这就是我要找的