objRA_Campaigns.StartDate = DateTime.ParseExact(tbAgentsAgentComparisonByQuestionaireFrom.Text, "yyyy/MM/dd HH:mm:ss", CultureInfo.InvariantCulture, DateTimeStyles.None);
asp.net calendar extender
<td style="padding-top: 5px; *padding-top: 3px; padding-left: 2px;" valign="middle">
<asp:TextBox ID="tbAgentsAgentComparisonByQuestionaireFrom" runat="server" CssClass="textBoxStyle"
meta:resourcekey="tbAgentsAgentComparisonByQuestionaireFromResource1"
Width="282px"></asp:TextBox>
<asp:ImageButton ID="imgDateCampaignStart" runat="server" CssClass="imgbutton" ImageUrl="~/Images/Calendar.png"
meta:resourcekey="imgDateCampaignStartResource1" />
<cc1:CalendarExtender ID="calAgentsAgentComparisonByQuestionaireFrom" runat="server"
Format="dd-MM-yyyy" PopupButtonID="imgDateCampaignStart" TargetControlID="tbAgentsAgentComparisonByQuestionaireFrom"
Enabled="True">
</cc1:CalendarExtender>
</td>
Exception is string is not in date time format.
Your
CalendarExtender
hasdd-MM-yyyy
as format, and you're parsing it asyyyy/MM/dd HH:mm:ss
. Both formats should match for the parse to be possible.