How to access Dataset from.cs to .aspx using eval() - c#

I am coding Gridview programmatically.
I have dataset in code behind part(.cs),when i am trying to access the dataset in .aspx page using Eval() "Error Creating Control" error is coming.
Is it the Right way using Eval()?
<asp:TemplateField>
<ItemTemplate>
<asp:Label ID="lblGridTier" runat="server" Text='<%#Eval(dt.Tables[0].Columns["Tier"])%>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>

If you are doing something like this in the code behind to bind the GridView (and you actually should do something like this):
DateSet ds = ...
GridView1.DataSource = ds;
GridView1.DataBind();
then the correct way to use eval is to give it just the name of the column you want to show.
Text='<%#Eval("Tier")%>'

ok please note html is rendered first then your code behind file is called. Now here dataset is null (not yet created) when HTML is being rendered dataset is null so control will not be created and an exception will be thrown. You can use this work around on Page_Load you can set text property of label or check here if dataset is null then don't assign value using Eval. Hope it will help.

Eval function evaluates fields directly from the selected table of datasource which your grid is bound with. A couple of examples as follows:
<asp:TemplateField>
<ItemTemplate>
<asp:Label ID="lblSomeField" runat="server" Text='<%# Eval("field1")%>'></asp:Label>
<asp:Image ID="lblImageLink" runat="server" ImageUrl='<%# Eval("imagefield", "http://somelink.com/images/{0}")%>' />
<asp:HyperLink ID="lblMember" runat="server" NavigateUrl='<%# "/member.aspx?id=" + Eval("id") %>' Text='<%# Eval("membername") %>'></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>

Related

Can't retrieve new value from GridView template field

I am having trouble retrieving the new value that is entered in a textbox template field in my GridView.
Here is my markup:
<asp:TemplateField HeaderText="username" SortExpression="username">
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Bind("username") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtUserName" runat="server" Text='<%# Bind("username") %>'></asp:TextBox>
</EditItemTemplate>
</asp:TemplateField>
And here is how I'm trying to retrieve the new value, inside the RowCommand event handler of my GridView:
string userName = ((TextBox)grdUserList.Rows[rowIndex].FindControl("txtUserName")).Text;
I get the old value instead of the newly typed value when I execute this code.
Does anyone know what I am missing? Thanks in advance.
I just found out the solution for my problem. I searched and found out that the GridView is being refreshed before the retrieving process begins because I was rebinding the GridView on the Page_Load method. I fixed the problem by not rebinding the gridview when it is a post back (or at least not before I have made the changes) using the IsPostback method. Thanks for everyone's reply :)
You are retrieving new value in wrong GridView event. You have to add OnRowUpdating="grdUserList_RowUpdating" event in your GridView control and then retrieve new TextBox value.
OnRowUpdating event in code-behind:
protected void grdUserList_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
string userName = ((TextBox)grdUserList.Rows[e.RowIndex].FindControl("txtUserName")).Text;
// Write your update query and logic over here.
}
You can take a reference from here for additional knowledge.
Please let me know if you have any questions.
use this code in gridview
<Columns>
<asp:TemplateField HeaderText="SrNo">
<EditItemTemplate>
<asp:TextBox ID="txtsrno" runat="server" Text='<%#Eval("SrNo") %>'>
</asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblsrno" runat="server" Text='<%#Eval("SrNo") %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>

How to select a cell in datagrid onClick in ASP.net C#

I am importing a column in datatable to my grid. Now I want navigate to a new page on selecting a cell in grid by fetching the selected value. I have tried this by including bound field in my grid like
<asp:GridView ID="GDV_1" runat="server" EnableModelValidation="true" AutoGenerateColumns="false" OnSelectedIndexChanged="GDV_1_SelectedIndexChanged" AutoGenerateSelectButton="false" DataKeyNames="SROID">
<Columns>
<asp:BoundField DataField="SRONameinEnglish" HtmlEncode="False" DataFormatString="<a target='_blank' href='Test.aspx?code={0}>ClickHere</a>" />
</Columns>
</asp:GridView>
Doing this way my requirement is achieved but the all cells are displaying Common text Click here instead of showing data from Database.
Please give your suggestion on how to get the value from database into cell and make it clickable. I don't want to use Select button. Please find my current output.
This is my current output I want my data from DB instead of ClickHere.
You can use TemplateField
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:LinkButton runat="server" ID="lnk<%# Eval("SRONameinEnglish")%>"><%# Eval("SRONameinEnglish")%></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
and click of LinkButton put your code to navigate anywhere.
In your case you are binding boundfield with static a tag which have href attribute so your not able to change text on that boundfield from your database.To get your approach you should
use TemplateField and bind data with text attribute using eval keyword as below example.
Try it:
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:HyperLink ID="HyperLink1" runat="server" Text='<%# Eval("name") %>' />
</ItemTemplate>
</asp:TemplateField>
OR
you can also bind link with your hyperlink using NavigateUrl property of hyperlink as below example.
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:HyperLink id="HyperLink2" NavigateUrl='<%#Eval("YourUrl") %>' Text='<%#Eval("name") %>' runat="server"/>
</ItemTemplate>
</asp:TemplateField>
I hope it will helpful to you.

asp.net bind a list to a gridview

List<MasterBook> listOfBooks = new List<MasterBook>();
after i put the masterbook objects which by the way have 3 fields( name,id and active ) into the list
GridView1.DataSource = listOfBooks;
GridView1.DataBind();
in the web form
<Columns>
<asp:TemplateField HeaderText="Book Name">
<ItemTemplate>
<asp:Label ID="BookNameText" runat="server"
Text="<%#Container.DataItem%>">
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
the problem is that i want to display the bookmaster's name in the gridview column
this code print bookmaster in the column how can i make it type the name
Change:
<%#Container.DataItem%>
To:
<%#Eval("name")%>
Cast it to MasterBook:
Text="<%# ((MasterBook) Container.DataItem).Name %>">
The quick, dirty hack workaround is to overload the ToString() method of your MasterBookclass in order to return that name. Commit seppuku afterwards if you do it.
The elegant and graceful way is to make an object datasource. That way you can bind the grid view's columns to the objects' properties. In the case of a DataList or other templated data controls, you can bind your objects' properties to the data control's child controls in their templates.
The middle path is in hutchonoid's answer: evaluate a property of the object, not the object itself.
Use this sintax:
<asp:Label ID="BookNameText" runat="server"
Text="<%# ((MasterBook)Container.DataItem).Name %>">

Bind Literal control inside Gridview from codebehind.

I have a gridview which contains template fields in which every template field contains a litreal control, and I want to bind that grid view with my DataSet, please look into the code to find more.
Code to create DataSet-
DataTable Record = new DataTable();
Record.Columns.Add("zerker");
DataRow dr = Record.NewRow();
dr["zerker"] = "SomeText";
Record.Rows.Add(dr);
gvCustomres.DataSource = Record;
gvCustomres.DataBind();
Code to create GridView-
<asp:GridView ID="gvCustomres" runat="server" PageSize="4" AutoGenerateColumns="False" >
<Columns>
<asp:TemplateField HeaderText="Zerker">
<ItemTemplate>
<asp:Literal ID="zerkername" runat="server"></asp:Literal>
</ItemTemplate>
</asp:TemplateField>
</columns>
</asp:GridView>
Please help me to find correct way to do this.
Thanks,
Your code above is all right if you just want to bind Column "zerker" to your gridiview.
All you are missing is the Text Property for your Literal control.
<asp:Literal ID="zerkername" runat="server" Text='<%# Eval("zerker") %>'>
</asp:Literal>

GridView trouble in .Net

i think this maybe an easy one...
I have a Gridview, bound to a dataSource with this query:
select userid, name, phone from users
I need to change the content of the Name cell to a link, like so:
User's Name
so OnRowDataBound i'm doing this:
e.Row.Cells[1].Text = "" + e.Row.Cells[1].Text + "";
It all works fine this way. My problem is that i don't want to display the UserId column in the Gridview, but when i attribute it (asp attribute or server-side) Visible="false" to the BoundField UserId, i can't capture it's value to build the Name Cell.
Thanx for your help
Make your gridView to use template items instead of simple grivdiew column.
<asp:TemplateField HeaderText="FirstName" SortExpression="FirstName">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("FirstName")%>'>
</asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("FirstName") %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
You can find a nice intro Here
Agree with Jani, this should be done with a template field. If you really need to do it the other way, see Can data be kept in a dynamically bound GridView's invisible fields?.
you can set the visibility on the onrowdatabound event

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