索引和长度必须引用该字符串内的位置。参数名: length

[yn011]

public partial class manage_editnews : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (Session["username"] == null)
{
Response.Redirect("~/login.aspx");
}
if (!IsPostBack)
{
band();
bindgrid();
}
}
private void band()//---绑定dripdownlist控件数据，用于绑定新闻类型
{
SqlConnection con = conn.createconn();
con.Open();
string aa = "select typename from newstype";
SqlDataAdapter sda = new SqlDataAdapter();
sda.SelectCommand = new SqlCommand(aa, con);
DataSet ds = new DataSet();
sda.Fill(ds);
this.droptype.DataSource = ds;//绑定dripdownlist
this.droptype.DataTextField = "typename";
this.droptype.DataValueField = "typename";
this.droptype.DataBind();

}
private void bindgrid()
{
SqlConnection con = conn.createconn();//---绑定GridView1控件数据，用于绑定新闻类型
con.Open();
string aa = "select adid, adname, adsubject, adtype, adcontent, adhit, addata from news";
SqlDataAdapter sda = new SqlDataAdapter();
sda.SelectCommand = new SqlCommand(aa, con);
DataSet ds = new DataSet();
sda.Fill(ds);
this.GridView1.DataSource = ds;
this.GridView1.DataBind();
con.Close();
}

public string GetContent(string str)
{
int i = str.Length;
string substr =str.Substring(0,5)+"....";
//在这里出错：用户代码未处理ArgumentOutOfRangeException return substr ;
}

protected void btnedit_Click1(object sender, EventArgs e)
{
if(Convert.ToInt32(ViewState["adid"])==0)
{
Response.Write("<script>alert('你还没有选择要更新的数据！');</script>");
}
else
{
SqlConnection con = conn.createconn();
con.Open();
int aa = Convert.ToInt32(ViewState["adid"]);
string str = "select adid,adsubject,adtype,adcontent from news where adid=" + aa + " ";
SqlCommand cmd = new SqlCommand(str, con);
SqlDataReader rd = cmd.ExecuteReader();
if (rd.Read())
{
tsubject.Text = rd["adsubject"].ToString();
tcontent.Text = rd["adcontent"].ToString();
this.droptype.Text = rd["adtype"].ToString();
}
con.Close();
this.p1.Visible = true;
this.p2.Visible = false;
}

}

protected void btneditnew_Click(object sender, EventArgs e)
{
if (15 > Length(this.tcontent.Text))
{
Response.Write("<script>alert('新闻内容不能少于15个字符！');</script>");
}
else
{
SqlConnection con = conn.createconn();
con.Open();

int aa = Convert.ToInt32(ViewState["adid"]);
string str = "update news set adsubject = '" + this.tsubject.Text + "' ,adcontent= '" + tcontent.Text + "',adtype='" + this.droptype.SelectedValue + "',addata='" + DateTime.Now +"' where adid=" + aa + "";
SqlCommand cmd = new SqlCommand(str, con);
cmd.ExecuteNonQuery();
con.Close();
bindgrid();
Response.Write("<script>alert('更新成功！');</script>");
this.p2.Visible = true;
this.p1.Visible = false;
}
}
protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
int aa = Convert.ToInt32(this.GridView1.SelectedRow.Cells[0].Text);
ViewState["adid"] = aa;

}
protected void btndelt_Click1(object sender, EventArgs e)
{
if (Convert.ToInt32(ViewState["adid"]) == 0)
{
Response.Write("<script>alert('你还没有选择要删除的数据！');</script>");
}
else
{
btndelt.Attributes.Add("onClick", "javascript:return confirm('确定删除吗？');");
//Response.write("<script>return confirm('是否要删除此记录')</script>");
SqlConnection con = conn.createconn();
con.Open();
// string str = "delete from news where adid=" + Convert.ToInt32(DataGrid1.SelectedItem.Cells[0].Text) + " ";
int aa = Convert.ToInt32(ViewState["adid"]);
string str = "delete from news where adid=" + aa + "";
SqlCommand cmd = new SqlCommand(str, con);
cmd.ExecuteNonQuery();
con.Close();
bindgrid();
}
}

protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
this.GridView1.PageIndex = e.NewPageIndex;
bindgrid();

}
protected void btncannle_Click(object sender, EventArgs e)
{
this.p2.Visible = true;
this.p1.Visible = false;
}
public int Length(string str)
{
int length = str.Length;
//用户验证控件
Regex RegCHZN = new Regex("[\u4e00-\u9fa5]");
foreach (char c in str)
{
Match m = RegCHZN.Match(c.ToString());
if (m.Success)
{
length++;
}
}
return length;
}
}

[全国话费充值]

int i = str.Length;
if(i>=5) string substr =str.Substring(0,5)+"....";

[yn011]

string substr =str.Substring(0,5)+"....";
//在这里出错：用户代码未处理ArgumentOutOfRangeException
"索引和长度必须引用该字符串内的位置。参数名: length“ 为什么出现这个错误，请教高手!

[人生难得一只鸡]

  public string GetContent(string str)
        {
            string substr = string.Empty;
            int i = str.Length;
            if (!string.IsNullOrEmpty(str))
            {
                if (i > 5)
                {
                    substr = str.Substring(0, 5) + "....";
                }
                else
                {
                    substr = str;
                }
            }
            return substr ;
        }

[zorro911]

public string GetContent(string str)
{
　int i = str.Length;
　string substr = str;
　if(i > 5)
　{
　　string substr =str.Substring(0,5)+"....";
　}
　return substr;
}

[全国话费充值]

str的长度少于你的str.Substring(0,5),所以要报错.你的str长度必须>=5,Substring才不会报错

[机器人]

。。。。 连 index 越界都搞不定么？ 5 > Length 啦

[yn011]

[Quote=引用 3 楼 return_false 的回复:]
C# code

public string GetContent(string str)
{
string substr = string.Empty;
int i = str.Length;
if (!string.IsNullOrEmpty(str))
{
……
[/Quote]
问题解决了，谢谢！