如何选择LB项目

Question

我填写了~/prog$ cd ~$ mkdir sbox ~$ cd sbox ~/sbox$ HOME=`pwd` ~$ export HOME ~$ cabal install bytestring Config file path source is default config file. Config file /home/novadenizen/sbox/.cabal/config not found. Writing default configuration to /home/novadenizen/sbox/.cabal/config Warning: The package list for 'hackage.haskell.org' does not exist. Run 'cabal update' to download it. cabal: There is no package named 'bytestring'. You may need to run 'cabal update' to get the latest list of available packages. ~$ cabal update Downloading the latest package list from hackage.haskell.org ~$ cabal install aeson Resolving dependencies... Downloading bytestring-0.10.6.0... Downloading dlist-0.7.1.1... Configuring dlist-0.7.1.1... Downloading syb-0.5.1... Downloading transformers-0.4.3.0... Configuring syb-0.5.1... Building dlist-0.7.1.1... Building syb-0.5.1... Installed dlist-0.7.1.1 Configuring bytestring-0.10.6.0... Building bytestring-0.10.6.0... Configuring transformers-0.4.3.0... Installed syb-0.5.1 Building transformers-0.4.3.0... Installed transformers-0.4.3.0 Downloading mtl-2.2.1... Downloading primitive-0.6... Configuring primitive-0.6... Building primitive-0.6... Configuring mtl-2.2.1... Installed primitive-0.6 Downloading vector-0.10.12.3... Building mtl-2.2.1... Configuring vector-0.10.12.3... Installed mtl-2.2.1 Building vector-0.10.12.3... Installed bytestring-0.10.6.0 Downloading binary-0.7.5.0... Configuring binary-0.7.5.0... Building binary-0.7.5.0... Installed binary-0.7.5.0 Downloading text-1.2.1.1... Configuring text-1.2.1.1... Building text-1.2.1.1... Installed vector-0.10.12.3 Installed text-1.2.1.1 Downloading hashable-1.2.3.2... Configuring hashable-1.2.3.2... Building hashable-1.2.3.2... Installed hashable-1.2.3.2 Downloading scientific-0.3.3.8... Downloading unordered-containers-0.2.5.1... Configuring scientific-0.3.3.8... Configuring unordered-containers-0.2.5.1... Building scientific-0.3.3.8... Building unordered-containers-0.2.5.1... Installed scientific-0.3.3.8 Downloading attoparsec-0.13.0.0... Configuring attoparsec-0.13.0.0... Building attoparsec-0.13.0.0... Installed unordered-containers-0.2.5.1 Installed attoparsec-0.13.0.0 Downloading aeson-0.9.0.1... Configuring aeson-0.9.0.1... Building aeson-0.9.0.1... Installed aeson-0.9.0.1 ~$ 所有课程，所以条目是：

ListBox

我使用所有列名填充了Course #1 Course #2 Course #3 Course #4 ，因此条目为：

DropDownList

如何多选项目。

Answer 1

似乎这就是你想要的：

@"SELECT [Course] 
FROM [Table1] 
WHERE [" + dropdownlistID.SelectedItem.Value + "] IS NOT NULL"