Charith's Blog: November 2010

Tuesday, November 16, 2010

How to output web page as MS word document

public partial class Test : Page
{
    protected override void Render(HtmlTextWriter writer)
    {
        Response.Clear();
        Response.Buffer = true;
        Response.ContentType = "application/msword";
        StringBuilder sb = new StringBuilder();
        StringWriter stringWriter = new StringWriter(sb);
        HtmlTextWriter htmlTextWriter = new HtmlTextWriter(stringWriter);
        base.Render(htmlTextWriter);
        Response.Write(sb.ToString());
        Response.End();            
    }
}

Friday, November 12, 2010

How to keep track of selected file during a postback.

When you select a file and then do a postback, you will lose your selected file. This is because there is no ViewState for posted file in asp.net FileUpload control. This example is to demonstrate an idea of how to save the file in any-postback and if there is a selected file, then we save the file and show the fileName in a hyperlink to download or view,
Example:

<%@ Page Language="C#" %>
<html>
<head id="Head1" runat="server">
    <script runat="server">
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            if (this.fuFile.HasFile)
            {                
                string filePath = Server.MapPath(string.Format("~/Uploads/{0}", this.fuFile.FileName));
                if (!System.IO.File.Exists(filePath))
                {
                    this.fuFile.SaveAs(filePath);
                    this.linkSelectedFile.NavigateUrl

                        = this.ResolveUrl(string.Format("~/Uploads/{0}", this.fuFile.FileName));

                    this.linkSelectedFile.Text = this.fuFile.FileName;
                }
            }
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
        Select a File: <asp:FileUpload runat="server" ID="fuFile" />
        <asp:HyperLink runat="server" ID="linkSelectedFile" />
        <hr />
        <asp:DropDownList runat="server" ID="ddlItems" AutoPostBack="true">
            <asp:ListItem>Item One</asp:ListItem>
            <asp:ListItem>Item Two</asp:ListItem>
        </asp:DropDownList>
    </form>
</body>
</html>

Tuesday, November 02, 2010

How to disable past days in asp.net calender control

<%@ Page Language="C#" %>
<html>   
<head id="Head1" runat="server">  
    <script runat="server">
        protected void DisablePastDays(object sender, DayRenderEventArgs e)
        {
            if (e.Day.Date < DateTime.Now)
            {
                e.Cell.Enabled = false;
                e.Day.IsSelectable = false;
                e.Cell.BackColor = System.Drawing.Color.Gray;
            }
        } 
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <asp:Calendar runat="server" ID="calDate" OnDayRender="DisablePastDays" />
    </form>
</body>
</html>

How to add detail textbox opon the check of a check box

Demo:
Example:
Markup:

<%@ Page Language="C#" %>
<html>   
<head id="Head1" runat="server">  
</head>
<body>
    <form id="form1" runat="server">
        <asp:FreeCheckBox runat="server" 
            ID="freeCheckBox" 
            DetailPlaceHolderId="phDetails" 
            Text="Are you disabled?" 
            DetailLabel="Please please provide details" />
        <asp:PlaceHolder runat="server" ID="phDetails" />
        <hr />
        <asp:Button runat="server" ID="btnSave" Text="Save" />
    </form>
</body>
</html>

Control:

public class FreeCheckBox : CheckBox
{
    private TextBox txtDetail;
    private Panel pnlDetail;
    private string script = @"
    function ShowHideDetailPanel(detailPanel, source) {            
        var panel = document.getElementById(detailPanel);
        if (panel == undefined) return;
        if (source.checked == true)
            panel.style.display = ""block"";
        else
            panel.style.display = ""none"";
    }
";
    public string DetailLabel { get; set; }
    public string Details { get; set; }
    public string DetailPlaceHolderId { get; set; }
    public bool IsMultiline { get; set; }
    public FreeCheckBox()
    {
        this.DetailPlaceHolderId = string.Empty;
        this.IsMultiline = false;
    }
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        this.CreateControlHeirarchy();
    }
    public void CreateControlHeirarchy()
    {
        this.pnlDetail = new Panel() { ID = string.Concat(this.ID, "_DetailPanel"), CssClass = "DetailPanel" };
        this.txtDetail = new TextBox() { ID = string.Concat(this.ID, "_TextBox"), 
                                            CssClass = "DetailTextBox", TextMode = TextBoxMode.MultiLine };
        if (this.IsMultiline) this.txtDetail.TextMode = TextBoxMode.MultiLine;
        this.pnlDetail.Controls.Add(new Label() { Text = this.DetailLabel, CssClass = "DetailLabel" });
        this.pnlDetail.Controls.Add(this.txtDetail);
        PlaceHolder phDetail = this.Page.FindControl(this.DetailPlaceHolderId) as PlaceHolder;
        Control parent = this.Parent;
        while (phDetail == null)
        {
            phDetail = parent.FindControl(this.DetailPlaceHolderId) as PlaceHolder;
            if (phDetail == null) parent = parent.Parent;
            if (parent == null) break;
        }
        if (phDetail != null) phDetail.Controls.Add(pnlDetail);
        this.Attributes.Add("onclick", 
                string.Format("javascript:ShowHideDetailPanel('{0}', this)", pnlDetail.ClientID));
    }
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        if (this.Checked)
            this.pnlDetail.Attributes.Add("style", "display:block;");
        else
            this.pnlDetail.Attributes.Add("style", "display:none;");
    }
    protected override bool LoadPostData(string postDataKey, NameValueCollection postCollection)
    {
        bool value = base.LoadPostData(postDataKey, postCollection);
        if (this.Checked)
            this.Details = this.txtDetail.Text;
        return value;
    }
    protected override void OnPreRender(EventArgs e)
    {
        base.OnPreRender(e);
        this.Page.ClientScript.RegisterClientScriptBlock(
                this.GetType(), this.GetType().Name, this.script, true);
    }
}

How to download images

Demo:
Code:

<%@ Page Language="C#" %>
<html>   
<head id="Head1" runat="server">  
    <script runat="server">
        public void DownloadPicture(object sender, EventArgs e)
        {
            ImageButton button = sender as ImageButton;
            if (button != null)
            {
                string fileName = button.CommandArgument;
                this.Response.AddHeader("content-disposition", 
                    string.Format("attachment;filename={0}", Path.GetFileName(fileName)));
                this.Response.ContentType = "image/jpg";
                this.Response.WriteFile(this.Server.MapPath("~/Images/" + fileName));
            }
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <asp:ImageButton runat="server" ID="btnPic1" Text="Pic 1" CommandArgument="Image1.jpg" 
            OnClick="DownloadPicture" Width="100" Height="75" ImageUrl="~/Images/Image1.jpg" />
        <asp:ImageButton runat="server" ID="btnPic2" Text="Pic 2" CommandArgument="Image2.jpg" 
            OnClick="DownloadPicture" Width="100" Height="75" ImageUrl="~/Images/Image2.jpg" />
        <asp:ImageButton runat="server" ID="btnPic3" Text="Pic 3" CommandArgument="Image3.jpg" 
            OnClick="DownloadPicture" Width="100" Height="75" ImageUrl="~/Images/Image3.jpg" />
        <asp:ImageButton runat="server" ID="btnPic4" Text="Pic 4" CommandArgument="Image4.jpg" 
            OnClick="DownloadPicture" Width="100" Height="75" ImageUrl="~/Images/Image4.jpg"/>
        <asp:ImageButton runat="server" ID="btnPic5" Text="Pic 5" CommandArgument="Image5.jpg" 
            OnClick="DownloadPicture" Width="100" Height="75" ImageUrl="~/Images/Image5.jpg"/>
    </form>
</body>
</html>

Monday, November 01, 2010

How to implement a custom default button for a page

<%@ Page Language="C#" %>
<html>   
<head id="Head1" runat="server">
    <script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script>
    <script language="javascript">
        $(document).ready(function () {
            $(".TextBox").bind("keyup", function (evt) {
                evt = (evt) ? evt : window.event
                var charCode = (evt.which) ? evt.which : evt.keyCode
                if (charCode == 13)
                    __doPostBack('<%= btnDefault.UniqueID %>', '');
                return true;
            });
            $(".TextBox").bind("keypress", function (evt) {
                evt = (evt) ? evt : window.event
                var charCode = (evt.which) ? evt.which : evt.keyCode
                if (charCode == 13)
                    return false;
                return true;
            });
        });
    </script>      
    <script runat="server">
        protected void Default(object sender, EventArgs e)
        {
            Response.Write(string.Format("Default button clicked at {0}",DateTime.Now.ToString("hh:mm:ss")));
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <asp:TextBox runat="server" ID="TextBox1" CssClass="TextBox" onkeypress="return false" />
        <asp:TextBox runat="server" ID="TextBox2" CssClass="TextBox" onkeypress="return false" />
        <asp:TextBox runat="server" ID="TextBox3" CssClass="TextBox" onkeypress="return false" />
        <asp:TextBox runat="server" ID="TextBox4" CssClass="TextBox" onkeypress="return false" />
        <asp:TextBox runat="server" ID="TextBox5" CssClass="TextBox" onkeypress="return false" />        
        <hr />
        <asp:Button runat="server" ID="btnDefault" Text="Default" OnClick="Default" UseSubmitBehavior="false" />
        <asp:Button runat="server" ID="Button1" Text="Other" />
        <asp:Button runat="server" ID="Button2" Text="Other" />
        <asp:Button runat="server" ID="Button3" Text="Other" />
        <asp:Button runat="server" ID="Button4" Text="Other" />
        <asp:Button runat="server" ID="Button5" Text="Other" />
    </form>
</body>
</html>

How to add select other/details textbox next to selection

How to remember the TreeView selection during postbacks

Markup:

<asp:TreeView runat="server" ID="trvItems" EnableClientScript="false" />
<asp:Button runat="server" ID="btnSave" Text="Save" />

Code:

public partial class Test : Page
{
    protected List<string> SelectedNodes
    {
        get { return (List<string>)(ViewState["TREENODECOLLECTION"] ?? (ViewState["TREENODECOLLECTION"] = new List<string>())); }
        set { ViewState["TREENODECOLLECTION"] = value; }
    }
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        this.trvItems.TreeNodeExpanded += new TreeNodeEventHandler(TreeNodeExpanded);
        this.trvItems.TreeNodeCollapsed += new TreeNodeEventHandler(TreeNodeCollapsed);
        this.trvItems.SelectedNodeChanged += new EventHandler(SelectedNodeChanged);
        if (!this.IsPostBack)
        {
            this.InitalizeTreeView();
            this.trvItems.DataBind();
            this.trvItems.CollapseAll();
            this.SelectedNodes = new List<string>();
        }
        else
            this.SetExapandNodes(this.trvItems.Nodes);
            
    }
    protected void InitalizeTreeView()
    {
 
    }
    protected void SelectedNodeChanged(object sender, EventArgs e)
    {
            
    }
    protected void TreeNodeCollapsed(object sender, TreeNodeEventArgs e)
    {
        this.SelectedNodes.Remove(e.Node.Value);
        this.SetExapandNodes(this.trvItems.Nodes);
    }
    protected void TreeNodeExpanded(object sender, TreeNodeEventArgs e)
    {
        this.SelectedNodes.Add(e.Node.Value);
        this.SetExapandNodes(this.trvItems.Nodes);
    }
    protected void SetExapandNodes(TreeNodeCollection nodes)
    {
        foreach(TreeNode n in nodes)
        {
            if(this.SelectedNodes.Exists(x=>x.Equals(n.Value)))
                n.Expand();
            if(n.ChildNodes.Count>0)
                this.SetExapandNodes(n.ChildNodes);
        }
    }
}