我在gridview的RowDataBound中找不到行，给出了异常“索引超出范围。 必须为非负数，并且小于集合的大小。”

Question

i am working with gridview , i want change color of specific row into grid view thats why i must find row at rowdatabound event. How i find the row?

Source code:

protected void Page_Load(object sender, EventArgs e)
{
    string[] arr={"1","2","3","4"};
    GridView1.DataSource = arr;
    GridView1.DataBind();
}
protected void pagechangin(object sender, GridViewPageEventArgs e) {
    GridView1.PageIndex = e.NewPageIndex;
}
protected void databound(Object sender, GridViewRowEventArgs e) {
    GridViewRow grv=GridView1.Rows[0];
}

Answer 1

You must register an event-handler to handle an event. But you haven't shown us the aspx markup, so maybe you have missed to add the handler declaratively:

<asp:gridview id="GridView1" 
    onrowdatabound="GridView1_RowDataBound" 
    runat="server">
  </asp:gridview>

void GridView1_RowDataBound(Object sender, GridViewRowEventArgs e)
{
    if(e.Row.RowType == DataControlRowType.DataRow)
    {
         // e.Row is the GridViewRow
         e.Row.BackColor = System.Drawing.Color.Green;
    }
}

Update The reason for the IndexOutOfRangeException is that you are accessing the first row before it is created:

GridViewRow grv=GridView1.Rows[0];

This is a nasty one. RowDataBound is called for every GridViewRow , not only for the DataItems but also for the Header , Footer and Pager . The first one that will be created is the Header . But GridView.Rows does return only GridViewRows with RowType = DataRow . So you are trying to access the first "data-row" during the creation of the header row.

To fix it use the code above and check the RowType .

if(e.Row.RowType == DataControlRowType.DataRow)
{
    // now you ca safely access the first row in this way, 
    // altghough i assume that you should use my code above 
    // to set the color of every GridViewRow
    GridViewRow grv=GridView1.Rows[0]; 

Apart from that you should also DataBind the grid only if(!IsPostBack) as Dragan has mentioned if you're using ViewState (default).

Answer 2

Your page_load event handler is not correct. Yoou shouldn't load the data on every page load but only on the initial. Maybe this is causing problems.

Try this in your Page_Load method

if (!Page.IsPostback)
{
    //copy your code from above
}