Gridview中DataRowView的问题

jiyanchn 2009-07-22 06:57:57

我在Gridview中使用RowDataBound事件。然后我将每一行的数据放到DataRowView中。当我从DataRowView中提取但个数据时出现错误：System.NullReferenceException: Object reference not set to an instance of an object.错误出现在：string bID = RowView["businessID"].ToString();

我的代码如下



    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

    {

        DataRowView RowView = (DataRowView)e.Row.DataItem;

        string bID = RowView["businessID"].ToString();

        if (e.Row.RowState == DataControlRowState.Normal)

        {

            HyperLink BusinessLinkObject = (HyperLink)e.Row.FindControl("HyperLinkBusinessName");

            if (e.Row.Cells[9].Text == "餐馆美食")

                BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + RowView["businessID"];

        }

    }

我不明白的地方有两处：
1，就是为什么会有这个错误。
2，同样是使用RowView["businessID"]，为什么在这段代码的第四行会报错，在倒数第三行中使用却不报错？

请前辈执教！！谢谢！

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che2piaopiao 2009-07-22

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Convert.Tostring(Object)

chenguang79 2009-07-22

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如何修改上面的兄弟们已经说了。
因为你的值没有放在DataControlRowState.Normal之内。这样它会把栏目哪行也算上的。这样就会报错了

moduofanchen 2009-07-22

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protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

    {

                string bID = "";

        if (e.Row.RowState == DataControlRowState.Normal)

        {DataRowView RowView = (DataRowView)e.Row.DataItem;



            bID=RowView["businessID"].ToString();

            HyperLink BusinessLinkObject = (HyperLink)e.Row.FindControl("HyperLinkBusinessName");

            if (e.Row.Cells[9].Text == "餐馆美食")

                BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + bID;        }

    }

上面的错了

moduofanchen 2009-07-22

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 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

    {

        DataRowView RowView = (DataRowView)e.Row.DataItem;

        string bID = "";

        if (e.Row.RowState == DataControlRowState.Normal)

        {

            bID=RowView["businessID"].ToString();

            HyperLink BusinessLinkObject = (HyperLink)e.Row.FindControl("HyperLinkBusinessName");

            if (e.Row.Cells[9].Text == "餐馆美食")

                BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + bID;        }

    }

沉序员 2009-07-22

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yuanchangyuan2125 2009-07-22

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此异常表明你引用了一个空对象
RowView["businessID"].ToString(); 报错应该可以说明 businessID 取不到这个值
仔细检查一下你的设计器断点走一遍看看RowView["businessID"].ToString(); 是否能取到值。

gdjlc 2009-07-22

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再改下：



 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

    {       

        if (e.Row.RowType == DataControlRowType.DataRow)

        {

             DataRowView RowView = (DataRowView)e.Row.DataItem;

             string bID = RowView["businessID"].ToString();



            HyperLink BusinessLinkObject = (HyperLink)e.Row.FindControl("HyperLinkBusinessName");

            if (e.Row.Cells[9].Text == "餐馆美食")

                BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + bID;

        }

    }

gdjlc 2009-07-22

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BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + RowView["businessID"];

---------------------------------
BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + bID;

gdjlc 2009-07-22

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 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)

    {       

        if (e.Row.RowState == DataControlRowState.Normal)

        {

             DataRowView RowView = (DataRowView)e.Row.DataItem;

             string bID = RowView["businessID"].ToString();



            HyperLink BusinessLinkObject = (HyperLink)e.Row.FindControl("HyperLinkBusinessName");

            if (e.Row.Cells[9].Text == "餐馆美食")

                BusinessLinkObject.NavigateUrl = "restaurant.aspx?id=" + RowView["businessID"];

        }

    }