How to edit and read data in a SharePoint List - sharepoint

Question

I want to query a SharePoint list and want to use the data to be displayed in a usercontrol that I have created.
Earlier I had the data coming from a database.
Now I need to modify it to work with a SharePoint list.
Can you please guide me.
Grace.

Answer 1

SPList list = null;
SPListItemCollection LIC = null;
SPListItem listItem = null;
using (SPSite mainSite = new SPSite("http://sitewhereyourlistis"))
{
using (SPWeb mainWeb = mainSite.OpenWeb())
{
list = mainWeb.Lists["ListNameHere"];
//**You will most likely want to limit your return to a single record so I have created the caml to do so with the List Item ID
String caml = String.Format("<Where><Eq><FieldRef Name=\"ID\" /><Value Type=\"Counter\">{0}</Value></Eq></Where>", ListItemID);
SPQuery qry = new SPQuery();
qry.Query = caml;
LIC = list.GetItems(qry);
listItem = LIC[0];
//**Here is where you will fill your textboxes
txtTextBoxName.Text = listItem["ColumnNameHere"].toString();
//**The above statement likes to error out if the value is null so I like to use a custom Application Helper Function to prevent things like this.
//**My actual call to get the data would look like this.
txtTextBoxName.Text = EnsureTextValue(listItem, "ColumnNameHere");
// I added the Function Definition Below
}
}
public String EnsureTextValue(SPListItem item, String param)
{
String tmp = String.Empty;
try
{
tmp = item[param].ToString();
}
catch { "Run Debug Method or Whatever Here" }
return tmp;
}
I am not sure if I missed anything but this should get you close.
Hope it helps!

Answer 2

To get Distinct Values for the column Click Here
To edit the values in the list there is a nice post here

Answer 3

I have used this to Query the SharePoint List
using (SPWeb web = SPContext.Current.Site.RootWeb)
{
SPList mylist = web.Lists["listName"];
SPQuery query = new SPQuery();
query.Query = "<Where><Eq><FieldRef Name='columnName' /><Value Type='Text'>" + strXYZ+ "</Value></Eq></Where>";
SPListItemCollection items = mylist.GetItems(query);
tempDT = items.GetDataTable();
return tempDT;
}