如何检查DataRowView是否为null. [英] How to check DataRowView null or not.

问题描述

如何检查DataRowView是否为null.我在这里出现错误源不包含DataRows".

How to check DataRowView null or not. I got error "The source contains no DataRows" here.

if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DataRowView drView = (DataRowView)e.Row.DataItem;
                {
                    DataTable dtChildTable1 = ((DataTable)Session["dtAll"]).Select("ID=" + Convert.ToInt32(drView["ID"])).CopyToDataTable();
}

推荐答案

Its better if you use boolean AND operator as follow

if (if e.Row != null && e.Row.RowType == DataControlRowType.DataRow)
{
    DataRowView drView = (DataRowView)e.Row.DataItem;
    {
         DataTable dtChildTable1 = ((DataTable) Session["dtAll"]);
         if(dtChildTable1 != null)
         {
              DataTable dtNew = dtChildTable1.Select("ID=" + Convert.ToInt32( drView["ID"])).CopyToDataTable();
         }
    }
}

 Or <br />
you can create a reference to the DataRow[] Array instead of dtNew variable of or better to use var 

尝试(drView.Row != null).

关注链接

http://msdn.microsoft.com/en-us/library/system. data.datarow.isnull.aspx [ ^ ]

http://msdn.microsoft.com/en-us/library/ms178296％28v = vs.80％29.aspx [ ^ ]

Follow the links

http://msdn.microsoft.com/en-us/library/system.data.datarow.isnull.aspx[^]

http://msdn.microsoft.com/en-us/library/ms178296%28v=vs.80%29.aspx[^]

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