获取gridview里的dropdownlist的值时"未将对象引用设置到对象的实例"

Question

我在gridview里增加了两列 一列是一个RadioButtonList,另一列是一个DropDownListpageload里写了
if (!IsPostBack)
{}在获取gridview的选取行的值时,  RadioButtonList的值可以获取,但是DropDownList的值是"未将对象引用设置到对象的实例"为什么取不到DropDownList的值啊.

Answer 1

 DropDownList生成语句
for (i = 1; i <= bdsm; i++)
            {                DDownList1.Items.Add(new ListItem(i.ToString(), i.ToString()));
            }获取DropDownList值的语句
 DropDownList DDownList1 = (DropDownList)row.FindControl("DropDownList");
  ssbd = DDownList1.SelectedItem.ToString();

Answer 2

DropDownList生成语句
for (i = 1; i <= bdsm; i++)
  {  DDownList1.Items.Add(new ListItem(i.ToString(), i.ToString()));
  }
写在哪....

Answer 3

获取DropDownList值的语句
 DropDownList DDownList1 = (DropDownList)row.FindControl("DropDownList");
  ssbd = DDownList1.SelectedItem.Text.ToString();

Answer 4

 protected void list_SelectedIndexChanged(object sender, EventArgs e)
    {
        RadioButtonList rblidea = (RadioButtonList)row.FindControl("rblidea");
        if (rblidea.Items[0].Selected == true)
        {
            sftbr = "1";
        }
        else
        {
            sftbr = "0";
        }
        DropDownList DDownList1 = (DropDownList)row.FindControl("DropDownList");
        ssbd = DDownList1.SelectedItem.Text.ToString();}写在gridview的SelectedIndexChanged事件里

Answer 5

RadioButtonList rblidea = (RadioButtonList)row[i].FindControl("rblidea");

Answer 6

RadioButtonList的值是可以获取的,倒是DropDownList的值没办法获取.

Answer 7

你循环的哪个i的值应该是空的，你response出来看一下吧，应该是没有值的

Answer 8

ssbd = DDownList1.Text.ToString();

Answer 9

调试看看SQL取到  对象集合了么..如果没有SQL除了问题,如果有,就是给值的时候出了问题

Answer 10

取不到是对的！！！！ 下拉的ID已经被 GRIDVIEW改变了！！你看HTML代码就知道了！既然ROW能取的到，就能ROW.ITEM 取到 下拉所在的 列！ 然后再转换 DropDownList

Answer 11

你那样找肯定是错的  这样去找GridView1.SelectedRow.FindControl("XX");

Answer 12

建议用 JS去取值！获取 GRIDVIEW 控件， GRIDVIEW
document.getElementById("GRIDVIEW1").ROW 去取值

Answer 13

建了一个名为list的griview控件
有list_RowDataBound1和list_SelectedIndexChanged两件事件
 protected void list_RowDataBound1(object sender, GridViewRowEventArgs e)
    {
        e.Row.Height = 30;
        DataRowView drvSfhg;
        string strHg;
        int i;
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            //外观样式
            if (e.Row.RowIndex % 2 == 0)
                e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor=\"" + e.Row.Style["BACKGROUND-COLOR"] + "\"");
            else
                e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor=\"#EFF3F7\"");
            e.Row.Attributes.Add("onmouseover", "this.style.backgroundColor=\"#D1DDF1\"");
            //编号 
            e.Row.Cells[0].Text = (e.Row.RowIndex + 1).ToString();            drvSfhg = (DataRowView)e.Row.DataItem;
            strHg = drvSfhg.Row["sfhg"].ToString();            if (strHg == "1")
            {
                e.Row.Cells[4].Text = "是";
                e.Row.Cells[4].ForeColor = Color.Red;
            }
            else
            {
                e.Row.Cells[4].Text = "否";
            }                        RadioButtonList rblidea = (RadioButtonList)e.Row.FindControl("rblidea");
            HiddenField hditem = (HiddenField)e.Row.FindControl("hditem");
            DropDownList DDownList1 = (DropDownList)e.Row.FindControl("DDownList1");            if (hditem.Value == "1")
            {
                rblidea.Items[0].Selected = true;            }
            else
            {
                rblidea.Items[1].Selected = true;
            }
            //生成标段选择列表
            for (i = 1; i <= bdsm; i++)          
            {
                DDownList1.Items.Add(new ListItem(i.ToString(), i.ToString()));
                              
            }
        }
    }-------------------------------------------------------------------------
protected void list_SelectedIndexChanged(object sender, EventArgs e)
    {
        string zbggbm, qybm, ssbd, sftbr;
        zbggbm = Request.QueryString["sgzbbm"].ToString();
        GridViewRow row = list.SelectedRow;        
        qybm = row.Cells[3].Text.Trim();        RadioButtonList rblidea = (RadioButtonList)row.FindControl("rblidea");
        if (rblidea.Items[0].Selected == true)
        {
            sftbr = "1";
        }
        else
        {
            sftbr = "0";
        }
        DropDownList DDownList1 = (DropDownList)row.FindControl("DropDownList");             
        ssbd = DDownList1.Text.ToString();     
}

Answer 14

我把取值的那段改成了
DropDownList DDownList1 = (DropDownList)list.SelectedRow.Cells[7].FindControl("DropDownList");              ssbd = DDownList1.Text.ToString();     
还是一样的为空

Answer 15

DropDownList DDownList1 = (DropDownList)row.FindControl("DDownList1");  
  ssbd = DDownList1.Text.ToString();

Answer 16

试试这段：
DropDownList DDownList1 = (DropDownList)list.SelectedRow.Cells[7].FindControl("DDownList1");   
if(DDownList1 !=null)
{
ssbd = DDownList1.Text.ToString();   
}
else
{
     //write a log
}

Answer 17

我之前也是这个错误，但是后来我自己解决了，是取值的问题，对DropDownList来说，他是一个很特别的类，他的实例不是在gridview里面，有时间找到我的给你看看，只要对他先填充数据。