首頁 >後端開發 >C#.Net教程 >C# DataRow.ItemArray 屬性

C# DataRow.ItemArray 屬性

黄舟
黄舟原創
2017-02-21 11:03:143918瀏覽

DataRow.ItemArray 屬性
透過一個陣列來取得或設定此行的所有值。
命名空間:System.Data

組件:System.Data(在system.data.dll 中)

程式碼範例:


private void CreateRowsWithItemArray()
{
    // Make a DataTable using the function below.
    DataTable dt = MakeTableWithAutoIncrement();
    DataRow relation;
    // Declare the array variable.
    object [] rowArray = new object[2];
    // Create 10 new rows and add to DataRowCollection.
    for(int i = 0; i <10; i++)
    {
        rowArray[0]=null;
        rowArray[1]= "item " + i;
        relation = dt.NewRow();
        relation.ItemArray = rowArray;
        dt.Rows.Add(relation);
    }
    PrintTable(dt);
}
 
private DataTable MakeTableWithAutoIncrement()
{
    // Make a table with one AutoIncrement column.
    DataTable table = new DataTable("table");
    DataColumn idColumn = new DataColumn("id", 
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement = true;
    idColumn.AutoIncrementSeed = 10;
    table.Columns.Add(idColumn);

    DataColumn firstNameColumn = new DataColumn("Item", 
        Type.GetType("System.String"));
    table.Columns.Add(firstNameColumn);
    return table;
}
 
private void PrintTable(DataTable table)
{
    foreach(DataRow row in table.Rows)
    {
        foreach(DataColumn column in table.Columns)
        {
            Console.WriteLine(row[column]);
        }
    }
}

異常:



陣列中的值與其對應的 DataColumn 中的 DataType 不符。 ConstraintExceptionReadOnlyException*​​&*NoNullAllowedException
異常類型 條件

ArgumentException

*​​&*
陣列大於表中的列數。

InvalidCastException

*​​&*

*​​&*

編輯破壞了約束。

編輯試圖更改唯讀列的值。

编辑试图将空值放在 DataColumn 对象的 AllowDBNull 为 false 的列中。

DeletedRowInaccessibleException

该行已被删除。

DataRow.ItemArray 属性源代码实现:


public object[] ItemArray
{
	get
	{
		int defaultRecord = this.GetDefaultRecord();
		object[] array = new object[this._columns.Count];
		for (int i = 0; i < array.Length; i++)
		{
			DataColumn dataColumn = this._columns[i];
			array[i] = dataColumn[defaultRecord];
		}
		return array;
	}
	set
	{
		if (value == null)
		{
			throw ExceptionBuilder.ArgumentNull("ItemArray");
		}
		if (this._columns.Count < value.Length)
		{
			throw ExceptionBuilder.ValueArrayLength();
		}
		DataColumnChangeEventArgs dataColumnChangeEventArgs = null;
		if (this._table.NeedColumnChangeEvents)
		{
			dataColumnChangeEventArgs = new DataColumnChangeEventArgs(this);
		}
		bool flag = this.BeginEditInternal();
		for (int i = 0; i < value.Length; i++)
		{
			if (value[i] != null)
			{
				DataColumn dataColumn = this._columns[i];
				if (-1L != this.rowID && dataColumn.ReadOnly)
				{
					throw ExceptionBuilder.ReadOnly(dataColumn.ColumnName);
				}
				if (dataColumnChangeEventArgs != null)
				{
					dataColumnChangeEventArgs.InitializeColumnChangeEvent(dataColumn, value[i]);
					this._table.OnColumnChanging(dataColumnChangeEventArgs);
				}
				if (dataColumn.Table != this._table)
				{
					throw ExceptionBuilder.ColumnNotInTheTable(dataColumn.ColumnName, this._table.TableName);
				}
				if (-1L != this.rowID && dataColumn.ReadOnly)
				{
					throw ExceptionBuilder.ReadOnly(dataColumn.ColumnName);
				}
				if (this.tempRecord == -1)
				{
					this.BeginEditInternal();
				}
				object obj = (dataColumnChangeEventArgs != null) ? dataColumnChangeEventArgs.ProposedValue : value[i];
				if (obj == null)
				{
					if (dataColumn.IsValueType)
					{
						throw ExceptionBuilder.CannotSetToNull(dataColumn);
					}
					obj = DBNull.Value;
				}
				try
				{
					int proposedRecordNo = this.GetProposedRecordNo();
					dataColumn[proposedRecordNo] = obj;
				}
				catch (Exception e)
				{
					if (ADP.IsCatchableOrSecurityExceptionType(e) && flag)
					{
						this.CancelEdit();
					}
					throw;
				}
				this.LastChangedColumn = dataColumn;
				if (dataColumnChangeEventArgs != null)
				{
					this._table.OnColumnChanged(dataColumnChangeEventArgs);
				}
			}
		}
		this.EndEdit();
	}
}

以上就是C#  DataRow.ItemArray 属性的内容,更多相关内容请关注PHP中文网(www.php.cn)!


陳述:
本文內容由網友自願投稿,版權歸原作者所有。本站不承擔相應的法律責任。如發現涉嫌抄襲或侵權的內容,請聯絡admin@php.cn