How to limit label string length in GridView with Read More link?

Currently I used like this...

<asp:TemplateField HeaderText="Description">
 <ItemTemplate>
      <asp:Label ID="lblDescription" runat="server"
                Text=开发者_JAVA技巧'<%# Limit(Eval("Description"),40) %>' >
      </asp:Label>
 </ItemTemplate>

The helper function:

public static string Limit(object Desc, int length)
{
    StringBuilder strDesc = new StringBuilder();
    strDesc.Insert(0, Desc.ToString());

    if (strDesc.Length > length)
        return strDesc.ToString().Substring(0, length) + "..." + [Read More];
    else return strDesc.ToString();
}

But I have no idea how to put [Read More] link...

Do something like this.

Markup

<asp:TemplateField HeaderText="Description">
 <ItemTemplate>
      <asp:Label ID="lblDescription" runat="server"
                Text='<%# Limit(Eval("Description"),40) %>' 
                Tooltip='<%# Eval("Description") %>'>
      </asp:Label>
      <asp:LinkButton ID="ReadMoreLinkButton" runat="server"
                Text="Read More"
                Visible='<%# SetVisibility(Eval("Description"), 40) %>'
                OnClick="ReadMoreLinkButton_Click">
      </asp:LinkButton>
 </ItemTemplate>
</asp:TemplateField>

And code-behind

protected bool SetVisibility(object desc, int maxLength)
{
    var description = (string)desc;
    if (string.IsNullOrEmpty(description)) { return false; }
    return description.Length > maxLength;
}

protected void ReadMoreLinkButton_Click(object sender, EventArgs e)
{
    LinkButton button = (LinkButton)sender;
    GridViewRow row = button.NamingContainer as GridViewRow;
    Label descLabel = row.FindControl("lblDescription") as Label;
    button.Text = (button.Text == "Read More") ? "Hide" : "Read More";
    string temp = descLabel.Text;
    descLabel.Text = descLabel.ToolTip;
    descLabel.ToolTip = temp;
}

protected string Limit(object desc, int maxLength)
{
    var description = (string)desc;
    if (string.IsNullOrEmpty(description)) { return description; }
    return description.Length <= maxLength ? 
        description : description.Substring(0, maxLength)+ "...";
}

Add an invisible HtmlAnchor control after the Label. Try something like,

<asp:TemplateField HeaderText="Description">
 <ItemTemplate>
      <asp:Label ID="lblDescription" runat="server"
                Text='<%# Limit(Eval("Description"),40) %>' >
      </asp:Label>
      <a href="TheReadMorePage" ID="aReadMore" runat="server" Visible="false">[Read More]</a>
 </ItemTemplate>


if(strDesc.Length > length)
{
    var anchor = ((Label)Desc).NamingContainer.FindControl("aReadMore");
    anchor.Visible = true;
    return strDesc.ToString().Substring(0, length) + "...";
}

You can use Modal Popup dialog box:

In ASP.Net page:

<script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.js"></script>
<script type="text/javascript" src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>
<script type="text/javascript">
$(function() {
$('#btnReadMore').click(function() {
$("#popupdiv").dialog({
title: "jQuery Popup from Server Side",
width: 430,
height: 250,
modal: true,
buttons: {
Close: function() {
$(this).dialog('close');
}
}
});
});
})


<asp:TemplateField HeaderText="Description">
 <ItemTemplate>
      <asp:Label ID="lblDescription" runat="server"
                Text='<%# Limit(Eval("Description"),40) %>' 
                Tooltip='<%# Eval("Description") %>'>
      </asp:Label>
      <input type="button" id="btnReadMore" value="Show Modal Popup" />

 </ItemTemplate>
</asp:TemplateField>

<div>
<div id="popupdiv" title="Basic modal dialog" style="display: none">
</div>