前台添加一模版列,里面添加一个Button
<asp:TemplateField HeaderText="测试">
      <ItemTemplate>
           <asp:Button ID="Button1" CommandName="btn" runat="server" Style="position: relative" Text="Button" />
      </ItemTemplate>
</asp:TemplateField>


后台

protected void gv_Company_RowCommand(object sender, GridViewCommandEventArgs e){
        if (e.CommandName == "btn"){
             int index = Convert.ToInt32(e.CommandArgument);
             DataKey key = this.gv_Company.DataKeys[index];
            string str = key.Value.ToString();
         }
     }

    //行数据绑定
    protected void gv_Company_RowDataBound(object sender, GridViewRowEventArgs e){
        if (e.Row.RowType == DataControlRowType.DataRow){
            Button bt = new Button();
             bt = (Button)e.Row.Cells[6].FindControl("Button1");
             bt.CommandArgument = e.Row.RowIndex.ToString();
         }
     }

那么，如果是在GridView里已经设置了LinkButton为事件处理按钮，将通过以下方法获取索引
protected void gv_Company_RowCommand(object sender, GridViewCommandEventArgs e){
        if (e.CommandName == "btn"){        
               GridViewRow drv = ((GridViewRow)(((LinkButton)(e.CommandSource)).Parent.Parent));
               object result = (object)gv_Company.DataKeys[drv.RowIndex][int];//int为DataKeys位置
         }
     }