I want to use both capital and small letters for login c# windows form

Hello Nuru,

please check below link, you need to use, COLLATE SQL_Latin1_General_CP1_CS_AS to match case-sensitive check,

https://www.c-sharpcorner.com/blogs/how-to-do-case-sensitive-string-match-in-sql-server1

CREATE PROCEDURE [dbo].[tblUserSelect_Authenticate]
@Username nvarchar(50),
@Password nvarchar(50)
AS
BEGIN
SELECT * FROM tblUser WHERE Username = @Username AND Password = @Password COLLATE SQL_Latin1_General_CP1_CS_AS
END

Hello

You can try the below way to accomplish the task. try a case-insensitive comparison by using InvariantCultureIgnoreCase.

String userInput = "UserName";
String dbValue = "userName";

if (String.Equals(userInput, dbValue, StringComparison.InvariantCultureIgnoreCase)) {
  // Write a code 
}

Thanks

Hello NURU,

If you want to check capital and small letter in both then you can do following

string username = txtUsername.Text;
string password = txtPassword.Text;

if (string.Equals(username, "admin", StringComparison.OrdinalIgnoreCase) &&
	string.Equals(password, "password", StringComparison.OrdinalIgnoreCase)) {
	//Success
} else {
	//Fail
}

.Or

You can convert the vallue ToLower and compare with lower case only. 

Example : 

string username = txtUsername.Text.ToLower();
string password = txtPassword.Text.ToLower();

if (username == "admin" && password == "ad@123")
{
	//Success
}
else
{
	//Fail
}

Thanks

Naimish Makwana