Clear PictureBox Image pbMyImage.Image = null; Display image from byte array //Display the byte array MemoryStream mStream = new MemoryStream(); mStream.Write(MyImageByteArray, 0, Convert.ToInt32(MyImageByteArray.Length)); Bitmap bm = new Bitmap(mStream, false); mStream.Dispose(); pbNameImage.Image = bm;
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UPDATE queries
UPDATE query example //—– DO QUERY —– Command1 = new System.Data.SQLite.SQLiteCommand(Connection1); Command1.CommandText = @"UPDATE tblBookLanguages SET LanguageText = @LanguageText, LanguageImage = @LanguageImage WHERE LanguageId = @LanguageId"; Command1.Parameters.AddWithValue("@LanguageText", LanguageText); if (LanguageImage.Length > 0) Command1.Parameters.AddWithValue("@LanguageImage", LanguageImage); else Command1.Parameters.AddWithValue("@LanguageImage", DBNull.Value); Command1.Parameters.AddWithValue("@LanguageId", LanguageId); Command1.ExecuteNonQuery();
Array Values
Read Array from BLOB column if (Reader1[“LanguageImage”].GetType() != typeof(DBNull)) byte[] LanguageImage = (byte[])Reader1[“LanguageImage”];
Null values
Is column returned null? if (Reader1[“LanguageImage”].GetType() != typeof(DBNull)) LanguageImage = (byte[])Reader1[“LanguageImage”]; Set column to null Command1.Parameters.AddWithValue("@LanguageImage", DBNull.Value);
Reference
Pass A Reference To A Function, Method, etc Passing by reference enables function members, methods, properties, indexers, operators, and constructors to change the value of the parameters and have that change persist in the calling environment. You just use the ‘ref’ or ‘out’ keyword: ‘ref’ tells the compiler that the object is initialized before entering the […]
Images To Byte Array
Convert Image To Byte Array var image = new Bitmap(SourceImageFilename); ImageConverter converter = new ImageConverter(); byte[] MyImageArray = (byte[])converter.ConvertTo(image, typeof(byte[])); Convert Byte Array To Picture Box Image //Display the byte array MemoryStream mStream = new MemoryStream(); mStream.Write(MyImageByteArray, 0, Convert.ToInt32(MyImageByteArray.Length)); Bitmap bm = new Bitmap(mStream, false); mStream.Dispose(); pbMyPictureBox.Image = bm;
.Using Combo Boxes
Only permitting items in the list (YOU HAVE TO REMEMBER TO DO THIS TO STOP USERS ENTERING THEIR OWN VALUES!!!) DropDownStyle = DropDownList (Only accepts strings that are part of the selection list) Loading the contents of a comboBox at application startup Allowing User To Type Text To Find An Entry DropDownStyle = DropDownAutoCompleteMode = […]
Array Functions
Increase Array Size Array.Resize(ref myArr, myArr.Length + 5); //Resize the array to a bigger size (five elements larger – could be made smaller instead).
Open Database
//—– OPEN DATABASE —– Connection1 = new System.Data.SQLite.SQLiteConnection("data source=" + MyDatabaseFilePath); Connection1.SetPassword(SQLITE_DATABASE_FILE_PASSWORD); Connection1.Open();
SELECT Queries
SELECT Query Example Command1 = new System.Data.SQLite.SQLiteCommand(Connection1); Command1.CommandText = "SELECT * FROM MyTable WHERE SomeColumnName >= @StartValue AND SomeColumnName <= @EndValue"; Command1.Parameters.AddWithValue("@StartValue", 14); Command1.Parameters.AddWithValue("@EndValue", 28); System.Data.SQLite.SQLiteDataReader Reader1 = Command1.ExecuteReader(); { while (Reader1.Read()) { //MyVariable = Convert.ToString(Reader1[“SomeColumnName1”]); //MyVariable2 = Convert.ToInt32(Reader1[“SomeColumnName2”]); } } Reader1.Close(); Getting Count Of Rows Returned //Get the number of results that will be […]