如何取出gridview中的某行的某个值？

[mymamxfx]

这是我写的代码：但是在点击“选择”按钮里总是提示：


异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。

源错误:


行 50: protected void GridView1_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
行 51: {
行 52: string stag = this.GridView1.SelectedRow.Cells[0].Text.Trim().ToString();
行 53: ViewState["vsta"] = stag;
行 54: //this.TextBox1.Text = ViewState["vsta"].ToString();

－－－－－－－－－我的后台代码是：－－－－－－－－－－－－－

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Bind();
}
}
/// <summary>
/// 初始绑定gridview
/// </summary>

public void Bind()
{
string sql = "select distinct News_Tage from News_Table where News_Tage<>'{0}' and News_State='{1}'";
sql = string.Format(sql, "NULL", 1);
Comm(sql);
}
/// <summary>
/// 传入sql语句完成gridview的数据绑定
/// </summary>
/// <param name="Sql">传入sql语句完成gridview的数据绑定</param>

public void Comm(string Sql)
{
SqlConnection scon = new SqlConnection(DS.DataServer.ConnString);
//SqlCommand scom = new SqlCommand(Sql, scon);
scon.Open();
SqlDataAdapter da = new SqlDataAdapter(Sql, scon);
DataSet ds = new DataSet();
da.Fill(ds, "News_Table");
this.GridView1.DataSource = ds;
this.GridView1.DataBind();
scon.Close();
}
protected void GridView1_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
{
string stag = this.GridView1.SelectedRow.Cells[0].Text.Trim().ToString();
ViewState["vsta"] = stag;
//this.TextBox1.Text = ViewState["vsta"].ToString();
}

protected void Button1_Click(object sender, EventArgs e)
{
//将要删除的标签更改值为 NULL
string sql = "update News_Table set News_Tage='{0}' where News_Tage='{1}'";
//update News_Table set News_Tage='' where News_Tage=''
sql = string.Format(sql, "NULL", ViewState["vstag"]);
this.TextBox1.Text = sql;
SqlConnection scon = new SqlConnection(DS.DataServer.ConnString);
SqlCommand scom = new SqlCommand(sql, scon);
scon.Open();
scom.ExecuteNonQuery();
scon.Close();
Response.Write("<script>alert('删除成功')</script>");
Bind();//替换标签后重新绑定gridview
}

请各位能够帮帮我。。我真的十分感谢你的帮助。。

[brooklyng60]

string stag = this.GridView1.Rows[e.NewSelectedIndex].Cells[0].Text.Trim().ToString();

[JeffChung]

同意2楼的，要Change以后才能去获取，不要在Changing里做

[dengchenlu]

谁说放Changing里没用的啊

[Quote=引用 5 楼 brooklyng60 的回复:]
string stag = this.GridView1.Rows[e.NewSelectedIndex].Cells[0].Text.Trim().ToString();
[/Quote]

[xjbx]

[Quote=引用 1 楼 namhyuk 的回复:]
莫名其妙，SelectedIndexChaing, 还没Change呢，你怎么能取到GridView1.SelectedRow啊？

Chaing和Changed搞清楚哦。
[/Quote]

同意

[Ring850215]

[Quote=引用 5 楼 brooklyng60 的回复:]
string stag = this.GridView1.Rows[e.NewSelectedIndex].Cells[0].Text.Trim().ToString();
[/Quote]

同意

[William_tim]

不妨试下这个:
string stag = GridView1.SelectedRow.Cells[数据库列的序号].Text.ToString();

[namhyuk]

莫名其妙，SelectedIndexChaing, 还没Change呢，你怎么能取到GridView1.SelectedRow啊？

Chaing和Changed搞清楚哦。

[sfssmiss]

1.
if (e.Row.RowType == DataControlRowType.DataRow)
{
//鼠标滑过整行背景变色
e.Row.Attributes.Add("onmouseover", "currentcolor=this.style.backgroundColor;this.style.backgroundColor='#B0E2FF',this.style.fontWeight='';");
e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor=currentcolor,this.style.fontWeight='';");

HiddenField hfi_id = (HiddenField)e.Row.Cells[3].FindControl("hf_i_id");

if (e.Row.Cells[1].Text != "")
{
if (e.Row.Cells[1].Text == "1")
{
e.Row.Cells[1].Text = "厂家";
}
if (e.Row.Cells[1].Text == "2")
{
e.Row.Cells[1].Text = "供应商";
}
if (e.Row.Cells[1].Text == "3")
{
e.Row.Cells[1].Text = "厂家/供应商";
}
}

}


2.protected void gv_Factory_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
BC_FACTORYEntity FCEntity = new BC_FACTORYEntity();
string id = this.gv_Factory.DataKeys[e.RowIndex].Value.ToString();

}
3.
protected void gv_Factory_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == "up")
{
Response.Redirect("FEdit.aspx?fid=" + e.CommandArgument.ToString() + "&id=" + Request.QueryString["id"] + "");
}
}
4.
protected void DealWithData()
{

foreach (GridViewRow grvRow in gv_Factory.Rows)
{
Label lbl_AuditingName = (Label)grvRow.Cells[5].FindControl("lblAuditingName");//审核人

//审核人
if (lbl_AuditingName.Text != null && lbl_AuditingName.Text != "" && lbl_AuditingName.Text != "0")
{
lbl_AuditingName.Text = DF.getUserFullName(lbl_AuditingName.Text);
}
else
{
lbl_AuditingName.Text = "";
}
}

[sntyy]

你可以在
"string stag = this.GridView1.SelectedRow.Cells[0].Text.Trim().ToString(); "
上面加一行:
this.GridView1.SelectedIndex = e.NewSelectedIndex;
也可以行得通
原因就是SelectedIndex在这里还没有得到你选择的行

[sntyy]

this.GridView1.SelectedIndex = e.NewSelectedIndex;
string stag = this.GridView1.SelectedRow.Cells[0].Text.Trim().ToString();