Setting the LinqDataSource Where Clause using DateTime Column

Question

In C#.net, I have the following DataSource setup that I am trying to dynamically assign a WHERE clause to in the code behind...

<asp:LinqDataSource ID="LinqDataSource1" runat="server" 
     ContextTypeName="MyNameSpace.DataClasses1DataContext"
     TableName="MyTableWithADateTimeColumn" >
</asp:LinqDataSource>

The code behind looks something like this...

LinqDataSource1.Where = "MyDateColumn == DateTime(" + DateTime.Now + ")";

This gives me an error of ')' or ',' expected. I've also tried casting it inside quotation marks, as well, as without casting it as DateTime and with quotation marks...

LinqDataSource1.Where = @"MyDateColumn == """ + DateTime.Now + @""" ";

This gives me Operator '==' incompatible with operand types 'DateTime' and 'String'. I've tried several other ways, but I am obviously missing something here.

Similar code is working fine for strings.

bytebender · Accepted Answer · 2009-06-26 21:48:11Z

12

is it this? What about this then...

LinqDataSource1.Where = "MyDateColumn == DateTime.Parse(" + DateTime.Now + ")"; 
//can't create a date from string in constructor use .Parse()...

edited Jun 26, 2009 at 21:48

answered Jun 26, 2009 at 21:01

bytebender

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1 Comment

bytebender Over a year ago

take a look again... there is no new DateTime(string value) constructor you need to use DateTime.Parse(string value)...

Reed Copsey · Accepted Answer · 2009-06-26 21:53:49Z

2

I believe you need to include double quotes around the string being converted to a DateTime.

LinqDataSource1.Where = "MyDateColumn == DateTime(\"" + DateTime.Now.ToString() + "\")";

edited Jun 26, 2009 at 21:53

answered Jun 26, 2009 at 21:00

Reed Copsey

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1 Comment

BrianG Over a year ago

I had tried single quotes without the cast but hadn't thought to try them with the DateTime cast. Unfortunately it gives the error "Character literal must contain exactly one character"

Venugopal · Accepted Answer · 2010-06-08 15:04:22Z

1

LinqDataSource1.Where = "MyDateColumn == Convert.ToDateTime(\"" + DateTime.Now + "\")";

answered Jun 8, 2010 at 15:04

Venugopal

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Comments

David Hall · Accepted Answer · 2012-10-26 15:10:13Z

It's simple and straight forward:

Look in the page source of "asp:LinqDataSource" and add that clause in the "where" section.

Adding this through the wizard with a NULL parameter fails.

Here is an example:

<asp:LinqDataSource ID="LinqDataSource1" runat="server" ContextTypeName="MyDataContext"
    EntityTypeName="" GroupBy="MyItem" Select="new (key as Item1, Count() as TotalQuantity)"
    TableName="MyTable" 

    Where="Country == @Country &amp;&amp; DateProcessed == NULL">
    <WhereParameters>
        <asp:ControlParameter ControlID="ddlCountry" DefaultValue="US" 
            Name="Country" PropertyName="SelectedValue" Type="String" />
    </WhereParameters>
</asp:LinqDataSource>

2 revs · Accepted Answer · 2009-06-29 19:40:38Z

0

So the final solution as suggested by J.13.L looked like this...

LinqDataSource1.Where = @"MyDateColumn == DateTime.Parse(""" + MyDateTime + @""") ";

But since I didn't want to match on the time part of the date it really looked more like this...

LinqDataSource1.Where = @"MyDateColumn >= DateTime.Parse(""" + MyDateTime + @""") AND MyDateColumn < DateTime.Parse(""" + MyDateTime.AddDays(1) + @""")";

edited Jun 29, 2009 at 19:40

community wiki

2 revs
BrianG

Comments

Sedgar · Accepted Answer · 2009-09-10 16:57:03Z

0

Another programmatically way:

dataSource.WherePredicateParameters.Clear();
OrExpressionParameter expression = new OrExpressionParameter();
expression.Parameters.Add("Birthday", DbType.DateTime, Convert.ToDateTime(txtBirthday.Text).ToString());
dataSource.WherePredicateParameters.Add(expression);

answered Sep 10, 2009 at 16:57

Sedgar

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