c# - Format a date so it can be written into Oracle ("Not a valid month" error) -

having trouble finding proper syntax this. here's field on asp side:

<input type="text" id="ei_open_auditstartdt" class="datepicker" runat="server"      name="ei_open_auditstartdt" value='<%#eval("audit_start_date") %>'      style="width: 100px" /> 

here's part of code-behind in c#:

htmlinputtext ei_open_auditstartdt = (htmlinputtext)datagrid_open.rows[e.rowindex].findcontrol("ei_open_auditstartdt"); textbox ei_open_transcit = (textbox)datagrid_open.rows[e.rowindex].findcontrol("ei_open_transcit");  string startdt = string.format("{0:dd-mmm-yyyy}", ei_open_auditstartdt.value); string transcit = ei_open_transcit.text;  datagrid_rootcauses.editindex = -1;  oracleconnection conn = getconnection(); try {     using (oraclecommand cmd = new oraclecommand("cst_amr_write_openstatus", conn))     {         cmd.commandtype = commandtype.storedprocedure;          using (oracledataadapter da = new oracledataadapter(cmd))         {             cmd.parameters.addwithvalue("v_startdt", oracletype.datetime).value = startdt;             cmd.parameters.addwithvalue("v_transcit", oracletype.varchar).value = transcit; 

the problem is, when gets string startdt, still sees value as, say, "03/24/2017" instead of "24-mar-17", i'm getting "not valid month" error.

can see i'm doing wrong?

1. verify format of data stored in oracle db.

2. attempt insert data raw string, in format , see if succeeds.

that takes calling code out of possible variables affecting problem.

3. if still doesn't work, have @ stored procedure , figure out if it's converting formats without knowledge.

4. if don't have ability see stored procedure, going have try bunch of different formats in calling code until find right one.